Network Working Group A. Vaha-Sipila
Request for Comments: 2806 Nokia
Category: Standards Track April 2000
Network Working Group A. Vaha-Sipila
Request for Comments: 2806 Nokia
Category: Standards Track April 2000
URLs for Telephone Calls
用于电话呼叫的URL
Status of this Memo
本备忘录的状况
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
本文件规定了互联网社区的互联网标准跟踪协议，并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态，请参考当前版本的“互联网官方协议标准”（STD 1）。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (2000). All Rights Reserved.
版权所有（C）互联网协会（2000年）。版权所有。
Abstract
摘要
This document specifies URL (Uniform Resource Locator) schemes "tel", "fax" and "modem" for specifying the location of a terminal in the phone network and the connection types (modes of operation) that can be used to connect to that entity. This specification covers voice calls (normal phone calls, answering machines and voice messaging systems), facsimile (telefax) calls and data calls, both for POTS and digital/mobile subscribers.
本文档指定了URL（统一资源定位器）“tel”、“传真”和“调制解调器”方案，用于指定终端在电话网络中的位置以及可用于连接到该实体的连接类型（操作模式）。本规范涵盖POTS和数字/移动用户的语音呼叫（普通电话呼叫、应答机和语音信息系统）、传真（传真）呼叫和数据呼叫。
Table of Contents
目录
1. Introduction ................................................ 2
1.1 New URL schemes ............................................ 2
1.2 Formal definitions ......................................... 3
1.3 Requirements ............................................... 3
2. URL schemes for telephone calls ............................. 3
2.1 Applicability .............................................. 3
2.2 "tel" URL scheme ........................................... 4
2.3 "fax" URL scheme ........................................... 6
2.4 "modem" URL scheme ......................................... 6
2.5 Parsing telephone, fax and modem URLs ...................... 7
2.5.1 Call type ................................................ 7
2.5.2 Phone numbers and their scope ............................ 7
2.5.3 Separators in phone numbers .............................. 10
2.5.4 Converting the number to the local numbering scheme ...... 10
2.5.5 Sending post-dial sequence after call setup .............. 10
2.5.6 Pauses in dialing and post-dial sequence ................. 11
2.5.7 ISDN subaddresses ........................................ 11
1. Introduction ................................................ 2
1.1 New URL schemes ............................................ 2
1.2 Formal definitions ......................................... 3
1.3 Requirements ............................................... 3
2. URL schemes for telephone calls ............................. 3
2.1 Applicability .............................................. 3
2.2 "tel" URL scheme ........................................... 4
2.3 "fax" URL scheme ........................................... 6
2.4 "modem" URL scheme ......................................... 6
2.5 Parsing telephone, fax and modem URLs ...................... 7
2.5.1 Call type ................................................ 7
2.5.2 Phone numbers and their scope ............................ 7
2.5.3 Separators in phone numbers .............................. 10
2.5.4 Converting the number to the local numbering scheme ...... 10
2.5.5 Sending post-dial sequence after call setup .............. 10
2.5.6 Pauses in dialing and post-dial sequence ................. 11
2.5.7 ISDN subaddresses ........................................ 11
2.5.8 T.33 subaddresses ........................................ 11
2.5.9 Data call parameters ..................................... 12
2.5.10 Telephony service provider identification ............... 13
2.5.11 Additional parameters ................................... 14
2.6 Examples of Use ............................................ 14
2.7 Rationale behind the syntax ................................ 15
2.7.1 Why distinguish between call types? ..................... 15
2.7.2 Why "tel" is "tel"? ..................................... 16
2.7.3 Why to use E.164-style numbering? ........................ 16
2.7.4 Not everyone has the same equipment as you ............... 17
2.7.5 Do not confuse numbers with how they are dialled ......... 17
3. Comments on usage ........................................... 17
4. References .................................................. 18
5. Security Considerations ..................................... 19
6. Acknowledgements ............................................ 20
7. Author's Address ............................................ 20
8. Full Copyright Statement .................................... 21
2.5.8 T.33 subaddresses ........................................ 11
2.5.9 Data call parameters ..................................... 12
2.5.10 Telephony service provider identification ............... 13
2.5.11 Additional parameters ................................... 14
2.6 Examples of Use ............................................ 14
2.7 Rationale behind the syntax ................................ 15
2.7.1 Why distinguish between call types? ..................... 15
2.7.2 Why "tel" is "tel"? ..................................... 16
2.7.3 Why to use E.164-style numbering? ........................ 16
2.7.4 Not everyone has the same equipment as you ............... 17
2.7.5 Do not confuse numbers with how they are dialled ......... 17
3. Comments on usage ........................................... 17
4. References .................................................. 18
5. Security Considerations ..................................... 19
6. Acknowledgements ............................................ 20
7. Author's Address ............................................ 20
8. Full Copyright Statement .................................... 21
This specification defines three new URL schemes: "tel", "fax" and "modem". They are intended for describing a terminal that can be contacted using the telephone network. The description includes the subscriber (telephone) number of the terminal and the necessary parameters to be able to successfully connect to that terminal.
本规范定义了三种新的URL方案：“电话”、“传真”和“调制解调器”。它们用于描述可以使用电话网络联系的终端。描述包括终端的用户（电话）号码以及能够成功连接到该终端的必要参数。
The "tel" scheme describes a connection to a terminal that handles normal voice telephone calls, a voice mailbox or another voice messaging system or a service that can be operated using DTMF tones.
“tel”方案描述了与处理正常语音电话呼叫的终端、语音信箱或另一语音消息系统或可使用DTMF音操作的服务的连接。
The "fax" scheme describes a connection to a terminal that can handle telefaxes (facsimiles). The name (scheme specifier) for the URL is "fax" as recommended by [E.123].
“传真”方案描述了与能够处理传真（传真机）的终端的连接。URL的名称（方案说明符）为[E.123]推荐的“传真”。
The "modem" scheme describes a connection to a terminal that can handle incoming data calls. The term "modem" refers to a device that does digital-to-analog and analog-to-digital conversions; in addition to these, a "modem" scheme can describe a fully digital connection.
“调制解调器”方案描述了与能够处理传入数据呼叫的终端的连接。术语“调制解调器”指进行数字到模拟和模拟到数字转换的设备；除此之外，“调制解调器”方案还可以描述全数字连接。
The notation for phone numbers is the same which is specified in
[RFC2303] and [RFC2304]. However, the syntax definition is a bit
different due to the fact that this document specifies URLs whereas
[RFC2303] and [RFC2304] specify electronic mail addresses. For
example, "/" (used in URLs to separate parts in a hierarchical URL
[RFC2396]) has been replaced by ";". In addition, this URL scheme has
been synchronized with [RFC2543].
The notation for phone numbers is the same which is specified in
[RFC2303] and [RFC2304]. However, the syntax definition is a bit
different due to the fact that this document specifies URLs whereas
[RFC2303] and [RFC2304] specify electronic mail addresses. For
example, "/" (used in URLs to separate parts in a hierarchical URL
[RFC2396]) has been replaced by ";". In addition, this URL scheme has
been synchronized with [RFC2543].
When these URLs are used, the number of parameters should be kept to the minimum, unless this would make the context of use unclear. Having a short URL is especially important if the URL is intended to be shown to the end user, printed, or otherwise distributed so that it is visible.
当使用这些URL时，参数的数量应保持在最小，除非这会使使用上下文不清楚。如果要向最终用户显示、打印或以其他方式分发URL以使其可见，则具有短URL尤其重要。
The ABNF (augmented Backus-Naur form) notation used in formal definitions follows [RFC2234]. This specification uses elements from the 'core' definitions (Appendix A of [RFC2234]). Some elements have been defined in previous RFCs. If this is the case, the RFC in question has been referenced in comments.
在正式定义中使用的ABNF（增广巴科斯-诺尔形式）符号如下[RFC2234]。本规范使用“核心”定义（RFC2234附录A）中的元素。一些元素已在以前的RFC中定义。如果是这种情况，则相关RFC已在注释中引用。
Note on non-unreserved characters [RFC2396] in URLs: the ABNF in this document specifies strings of raw, unescaped characters. If those characters are present in a URL, and are not unreserved [RFC2396], they MUST be escaped as explained in [RFC2396] prior to using the URL. In addition, when parsing a URL, it must be noted that some characters may have been escaped.
关于URL中的非保留字符[RFC2396]的注意事项：本文档中的ABNF指定原始的、未转换字符的字符串。如果这些字符存在于URL中，并且不是无保留的[RFC2396]，则在使用URL之前，必须按照[RFC2396]中的说明对其进行转义。此外，在解析URL时，必须注意某些字符可能已转义。
An example: ABNF notation "%x20" means a single octet with a hexadecimal value of "20" (in US-ASCII, a space character). This must be escaped in a URL, and it becomes "%20".
例如：ABNF符号“%x20”表示十六进制值为“20”的单个八位字节（在US-ASCII中，是一个空格字符）。这必须在URL中转义，它将变为“%20”。
In addition, the ABNF in this document only uses lower case. The URLs are case-insensitive (except for the <future-extension> parameter, whose case-sensitivity is application-specific).
此外，本文档中的ABNF仅使用小写。URL不区分大小写（除了<future extension>参数，该参数区分大小写是特定于应用程序的）。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照[RFC2119]中所述进行解释。
Compliant software MUST follow this specification.
兼容软件必须遵循此规范。
In this document, "local entity" means software and hardware that can detect and parse one or more of these URLs and possibly place a call to a remote entity, or otherwise utilize the contents of the URL.
在本文档中，“本地实体”是指能够检测和解析一个或多个URL，并可能调用远程实体，或以其他方式利用URL内容的软件和硬件。
These URL schemes are used to direct the local entity to place a call using the telephone network, or as a method to transfer or store a phone number plus other relevant data. The network in question may be
这些URL方案用于指导本地实体使用电话网络拨打电话，或作为传输或存储电话号码和其他相关数据的方法。有问题的网络可能是
a landline or mobile phone network, or a combination of these. If the phone network differentiates between (for example) voice and data calls, or if the local entity has several different telecommunications equipment at its disposal, it is possible to specify which kind of call (voice/fax/data) is requested. The URL can also contain information about the capabilities of the remote entity, so that the connection can be established successfully.
固定电话或移动电话网络，或两者的组合。如果电话网络区分（例如）语音呼叫和数据呼叫，或者如果本地实体有多个不同的电信设备可供使用，则可以指定请求哪种呼叫（语音/传真/数据）。URL还可以包含有关远程实体功能的信息，以便成功建立连接。
The "tel", "fax" and "modem" URL schemes defined here do not use the hierarchical URL syntax; there are no applicable relative URL forms. The URLs are always case-insensitive, except for the <future-extension> parameter (see below), whose case-sensitivity is application specific. Characters in the URL MUST be escaped when needed as explained in [RFC2396].
此处定义的“tel”、“fax”和“modem”URL方案不使用分层URL语法；没有适用的相对URL表单。URL总是不区分大小写，除了<future extension>参数（见下文），该参数区分大小写是特定于应用程序的。如[RFC2396]所述，URL中的字符在需要时必须转义。
The URL syntax is formally described as follows. For the basis of this syntax, see [RFC2303].
URL语法正式描述如下。有关此语法的基础，请参见[RFC2303]。
telephone-url = telephone-scheme ":"
telephone-subscriber
telephone-scheme = "tel"
telephone-subscriber = global-phone-number / local-phone-number
global-phone-number = "+" base-phone-number [isdn-subaddress]
[post-dial] *(area-specifier /
service-provider / future-extension)
base-phone-number = 1*phonedigit
local-phone-number = 1*(phonedigit / dtmf-digit /
pause-character) [isdn-subaddress]
[post-dial] area-specifier
*(area-specifier / service-provider /
future-extension)
isdn-subaddress = ";isub=" 1*phonedigit
post-dial = ";postd=" 1*(phonedigit /
dtmf-digit / pause-character)
area-specifier = ";" phone-context-tag "=" phone-context-ident
phone-context-tag = "phone-context"
phone-context-ident = network-prefix / private-prefix
network-prefix = global-network-prefix / local-network-prefix
global-network-prefix = "+" 1*phonedigit
local-network-prefix = 1*(phonedigit / dtmf-digit / pause-character)
private-prefix = (%x21-22 / %x24-27 / %x2C / %x2F / %x3A /
%x3C-40 / %x45-4F / %x51-56 / %x58-60 /
%x65-6F / %x71-76 / %x78-7E)
*(%x21-3A / %x3C-7E)
; Characters in URLs must follow escaping rules
; as explained in [RFC2396]
telephone-url = telephone-scheme ":"
telephone-subscriber
telephone-scheme = "tel"
telephone-subscriber = global-phone-number / local-phone-number
global-phone-number = "+" base-phone-number [isdn-subaddress]
[post-dial] *(area-specifier /
service-provider / future-extension)
base-phone-number = 1*phonedigit
local-phone-number = 1*(phonedigit / dtmf-digit /
pause-character) [isdn-subaddress]
[post-dial] area-specifier
*(area-specifier / service-provider /
future-extension)
isdn-subaddress = ";isub=" 1*phonedigit
post-dial = ";postd=" 1*(phonedigit /
dtmf-digit / pause-character)
area-specifier = ";" phone-context-tag "=" phone-context-ident
phone-context-tag = "phone-context"
phone-context-ident = network-prefix / private-prefix
network-prefix = global-network-prefix / local-network-prefix
global-network-prefix = "+" 1*phonedigit
local-network-prefix = 1*(phonedigit / dtmf-digit / pause-character)
private-prefix = (%x21-22 / %x24-27 / %x2C / %x2F / %x3A /
%x3C-40 / %x45-4F / %x51-56 / %x58-60 /
%x65-6F / %x71-76 / %x78-7E)
*(%x21-3A / %x3C-7E)
; Characters in URLs must follow escaping rules
; as explained in [RFC2396]
; See sections 1.2 and 2.5.2
service-provider = ";" provider-tag "=" provider-hostname
provider-tag = "tsp"
provider-hostname = domain ; <domain> is defined in [RFC1035]
; See section 2.5.10
future-extension = ";" 1*(token-char) ["=" ((1*(token-char)
["?" 1*(token-char)]) / quoted-string )]
; See section 2.5.11 and [RFC2543]
token-char = (%x21 / %x23-27 / %x2A-2B / %x2D-2E / %x30-39
/ %x41-5A / %x5E-7A / %x7C / %x7E)
; Characters in URLs must follow escaping rules
; as explained in [RFC2396]
; See sections 1.2 and 2.5.11
quoted-string = %x22 *( "\" CHAR / (%x20-21 / %x23-7E
/ %x80-FF )) %x22
; Characters in URLs must follow escaping rules
; as explained in [RFC2396]
; See sections 1.2 and 2.5.11
phonedigit = DIGIT / visual-separator
visual-separator = "-" / "." / "(" / ")"
pause-character = one-second-pause / wait-for-dial-tone
one-second-pause = "p"
wait-for-dial-tone = "w"
dtmf-digit = "*" / "#" / "A" / "B" / "C" / "D"
; See sections 1.2 and 2.5.2
service-provider = ";" provider-tag "=" provider-hostname
provider-tag = "tsp"
provider-hostname = domain ; <domain> is defined in [RFC1035]
; See section 2.5.10
future-extension = ";" 1*(token-char) ["=" ((1*(token-char)
["?" 1*(token-char)]) / quoted-string )]
; See section 2.5.11 and [RFC2543]
token-char = (%x21 / %x23-27 / %x2A-2B / %x2D-2E / %x30-39
/ %x41-5A / %x5E-7A / %x7C / %x7E)
; Characters in URLs must follow escaping rules
; as explained in [RFC2396]
; See sections 1.2 and 2.5.11
quoted-string = %x22 *( "\" CHAR / (%x20-21 / %x23-7E
/ %x80-FF )) %x22
; Characters in URLs must follow escaping rules
; as explained in [RFC2396]
; See sections 1.2 and 2.5.11
phonedigit = DIGIT / visual-separator
visual-separator = "-" / "." / "(" / ")"
pause-character = one-second-pause / wait-for-dial-tone
one-second-pause = "p"
wait-for-dial-tone = "w"
dtmf-digit = "*" / "#" / "A" / "B" / "C" / "D"
The URL starts with <telephone-scheme>, which tells the local entity that what follows is a URL that should be parsed as described in this document. After that, the URL contains the phone number of the remote entity. Phone numbers can also contain subaddresses, which are used to identify different remote entities under the same phone number. If a subaddress is present, it is appended to the phone number after ";isub=". Phone numbers can also contain a post-dial sequence. This is what is often used with voice mailboxes and other services that are controlled by dialing numbers from your phone keypad while the call is in progress. The <post-dial> sequence describes what and when the local entity should send to the phone line.
URL以<telephone scheme>开头，它告诉本地实体下面是一个URL，应该按照本文档中的描述进行解析。之后，URL包含远程实体的电话号码。电话号码还可以包含子地址，用于标识同一电话号码下的不同远程实体。如果存在子地址，则会将其附加到电话号码的“isub=”后面。电话号码也可以包含拨后序列。这是语音信箱和其他服务经常使用的功能，在通话过程中，语音信箱和其他服务通过从手机键盘拨号码来控制。<post dial>序列描述本地实体应发送到电话线的内容和时间。
Phone numbers can be either "global" or "local". Global numbers are unambiguous everywhere. Local numbers are usable only within a certain area, which is called "context", see section 2.5.2.
电话号码可以是“全球”或“本地”。全球数字在任何地方都是明确的。本地号码仅在特定区域内可用，称为“上下文”，见第2.5.2节。
Local numbers always have an <area-specifier>, which specifies the context in which the number is usable (the same number may have different interpretation in different network areas). The context can be indicated with three different prefixes. A <global-network-prefix> indicates that the number is valid within a numbering area whose global numbers start with <global-network-prefix>. Similarly, <local-network-prefix> means that the number is valid within a
本地号码总是有一个<area specifier>，指定号码可用的上下文（同一号码在不同的网络区域可能有不同的解释）。上下文可以用三个不同的前缀表示。<global network prefix>表示编号在全局编号以<global network prefix>开头的编号区域内有效。类似地，<local network prefix>表示该数字在
numbering area whose numbers (or dial strings) start with it. A <private-prefix> is a name of a context. The local entity must have knowledge of this private context to be able to deduce whether it can use the number, see section 2.5.2. Additional information about the phone number's usage can be included by adding the name of the telephony services provider in <service-provider>, see section 2.5.10.
编号区域，其号码（或拨号串）以其开头。<private prefix>是上下文的名称。本地实体必须了解该私有上下文，才能推断其是否可以使用该数字，请参见第2.5.2节。有关电话号码使用情况的其他信息，可通过在<service provider>中添加电话服务提供商的名称，参见第2.5.10节。
The <future-extension> mechanism makes it possible to add new parameters to this URL scheme. See section 2.5.11.
<future extension>机制可以向该URL方案添加新参数。见第2.5.11节。
The <private-prefix>, <token-char> and <quoted-string> nonterminals may seem a bit complex at first, but they simply describe the set of octets that are legal in those nonterminals. Some octets may have to be escaped, see [RFC2396].
<private prefix>、<token char>和<quoted string>非终结符起初可能有点复杂，但它们只是描述了在这些非终结符中合法的八位字节集。某些八位字节可能必须转义，请参见[RFC2396]。
The URL syntax is formally described as follows (the definition reuses nonterminals from the above definition). For the basis of this syntax, see [RFC2303] and [RFC2304].
URL语法的形式描述如下（定义重用上述定义中的非终端）。有关此语法的基础，请参见[RFC2303]和[RFC2304]。
fax-url = fax-scheme ":" fax-subscriber
fax-scheme = "fax"
fax-subscriber = fax-global-phone / fax-local-phone
fax-global-phone = "+" base-phone-number [isdn-subaddress]
[t33-subaddress] [post-dial]
*(area-specifier / service-provider /
future-extension)
fax-local-phone = 1*(phonedigit / dtmf-digit /
pause-character) [isdn-subaddress]
[t33-subaddress] [post-dial]
area-specifier
*(area-specifier / service-provider /
future-extension)
t33-subaddress = ";tsub=" 1*phonedigit
fax-url = fax-scheme ":" fax-subscriber
fax-scheme = "fax"
fax-subscriber = fax-global-phone / fax-local-phone
fax-global-phone = "+" base-phone-number [isdn-subaddress]
[t33-subaddress] [post-dial]
*(area-specifier / service-provider /
future-extension)
fax-local-phone = 1*(phonedigit / dtmf-digit /
pause-character) [isdn-subaddress]
[t33-subaddress] [post-dial]
area-specifier
*(area-specifier / service-provider /
future-extension)
t33-subaddress = ";tsub=" 1*phonedigit
The fax: URL is very similar to the tel: URL. The main difference is that in addition to ISDN subaddresses, telefaxes also have an another type of subaddress, see section 2.5.8.
fax:URL与tel:URL非常相似。主要区别在于，除了ISDN子地址外，电传还有另一种类型的子地址，请参见第2.5.8节。
The URL syntax is formally described as follows (the definition reuses nonterminals from the above definitions). For the basis of this syntax, see [RFC2303].
URL语法的形式描述如下（定义重用上述定义中的非终结符）。有关此语法的基础，请参见[RFC2303]。
modem-url = modem-scheme ":" remote-host
modem-scheme = "modem"
remote-host = telephone-subscriber *(modem-params
/ recommended-params)
modem-params = ";type=" data-capabilities
recommended-params = ";rec=" data-capabilities
data-capabilities = accepted-modem ["?" data-bits parity
stop-bits]
accepted-modem = "V21" / "V22" / "V22b" /
"V23" / "V26t" / "V32" /
"V32b" / "V34" / "V90" /
"V110" / "V120" / "B103" /
"B212" / "X75" /
"vnd." vendor-name "." modem-type
data-bits = "7" / "8"
parity = "n" / "e" / "o" / "m" / "s"
stop-bits = "1" / "2"
vendor-name = 1*(ALPHA / DIGIT / "-" / "+")
modem-type = 1*(ALPHA / DIGIT / "-" / "+")
modem-url = modem-scheme ":" remote-host
modem-scheme = "modem"
remote-host = telephone-subscriber *(modem-params
/ recommended-params)
modem-params = ";type=" data-capabilities
recommended-params = ";rec=" data-capabilities
data-capabilities = accepted-modem ["?" data-bits parity
stop-bits]
accepted-modem = "V21" / "V22" / "V22b" /
"V23" / "V26t" / "V32" /
"V32b" / "V34" / "V90" /
"V110" / "V120" / "B103" /
"B212" / "X75" /
"vnd." vendor-name "." modem-type
data-bits = "7" / "8"
parity = "n" / "e" / "o" / "m" / "s"
stop-bits = "1" / "2"
vendor-name = 1*(ALPHA / DIGIT / "-" / "+")
modem-type = 1*(ALPHA / DIGIT / "-" / "+")
The modem: URL scheme is also very similar to both the tel: and fax: schemes, but it adds the description of the capabilities of the remote entity. Minimum required compliance is listed in <modem-params> and recommended compliance is listed in <recommended-params>. For details, see section 2.5.9.
modem:URL方案也非常类似于tel:和fax:方案，但它添加了对远程实体功能的描述。<modem params>中列出了所需的最低合规性，而<recommended params>中列出了建议的合规性。有关详细信息，请参见第2.5.9节。
The type of call is specified by the scheme specifier. "Tel" means that a voice call is opened. "Fax" indicates that the call should be a facsimile (telefax) call. "Modem" means that it should be a data call. Not all networks differentiate between the types of call; in this case, the scheme specifier indicates the telecommunications equipment type to use.
调用类型由方案说明符指定。“电话”表示语音呼叫已打开。“传真”表示呼叫应为传真（电传）呼叫。“调制解调器”意味着它应该是一个数据呼叫。并非所有网络都能区分呼叫类型；在这种情况下，方案说明符指示要使用的电信设备类型。
<telephone-subscriber> and <fax-subscriber> indicate the phone number to be dialed. The phone number can be written in either international or local notation. All phone numbers SHOULD always be written in the international form if there is no good reason to use the local form.
<电话订户>和<传真订户>指示要拨打的电话号码。电话号码可以用国际或本地符号书写。如果没有充分理由使用本地表格，则所有电话号码应始终以国际表格书写。
Not all numbers are valid within all numbering areas. The <area-specifier> parameter, which is mandatory for local numbers, is used to indicate the locale within which this number is valid, or to qualify the phone number so that it may be used unambiguously. The
并非所有编号区域内的所有编号都有效。<area specifier>参数对于本地号码是必需的，用于指示此号码有效的区域设置，或限定电话号码以便可以明确使用。这个
<area-specifier> can take three forms: <global-network-prefix>, <local-network-prefix> or <private-prefix>. These are used to describe the validity area of the phone number either in global numbering plan, local numbering plan, or in a private numbering plan, respectively.
<area specifier>可以采用三种形式：<global network prefix>、<local network prefix>或<private prefix>。它们分别用于在全局编号计划、本地编号计划或专用编号计划中描述电话号码的有效区域。
If <area-specifier> is present, the local entity MUST NOT attempt to call out using the phone number if it cannot originate the call within the specified locale. If a <local-phone-number> is used, an <area-specifier> MUST be included as well.
如果存在<area specifier>，如果本地实体无法在指定区域内发起呼叫，则不得尝试使用电话号码呼叫。如果使用<本地电话号码>，则还必须包括<区域说明符>。
There can be multiple instances of <area-specifier>. In this case, the number is valid in all of the given numbering areas.
<area specifier>可以有多个实例。在这种情况下，该编号在所有给定编号区域都有效。
The global prefix form is intended to act as the outermost context for a phone number, so it will start with a "+", followed by some part of an E.164 number. It also specifies the region in which the phone number is valid. For example, if <global-network-prefix> is "+358", the given number is valid only within Finland (country code 358) - even if it is a <global-phone-number>.
全局前缀形式旨在充当电话号码的最外层上下文，因此它将以“+”开头，后跟E.164号码的某些部分。它还指定电话号码有效的地区。例如，如果<global network prefix>为“+358”，则给定的号码仅在芬兰境内有效（国家代码358）-即使它是<global phone number>。
The local prefix form is intended to act as an intermediate context in those situations where the outermost context for a phone number is given by another means. One example of use is where the local entity is known to originate calls only within the North American Number Plan Area, so an "outermost" phone context can be assumed. The local context could, for example, be used to indicate the area code within which an associated phone number is situated. Thus "tel:456- 7890;phone-context=213" would suffice to deliver a call to the telephone number "+1-213-456-7890". Note that the version including the <phone-context> implies further that the call can only be originated within the "area code 213" region.
本地前缀形式旨在在电话号码的最外层上下文通过另一种方式给出的情况下充当中间上下文。使用的一个示例是，已知本地实体仅在北美号码计划区域内发起呼叫，因此可以假设“最外层”电话上下文。例如，本地上下文可用于指示相关电话号码所在的区号。因此，“电话：456-7890；电话上下文=213”就足以拨打电话号码“+1-213-456-7890”。注意，包含<phone context>的版本进一步暗示呼叫只能在“区号213”区域内发起。
The <private-prefix> form is intended for use in those situations where the context cannot be expressed with a start of a global phone number or a dialing string. The <private-prefix> is actually a name of a private context. The creator of the URL and the local entity have been configured to recognize this name, and as such they can interpret the number and know how they can utilize the number. For example, a private network numbering plan may be indicated by the name "X-COMPANY-NET", but the private dialling plan from the locales of the sender of the telephony URL and the local entity are different. The syntax of these tokens will be left for future specification. The ABNF above specifies the accepted characters that can be a part of <private-prefix>.
<private prefix>表单用于无法以全局电话号码或拨号字符串开头表示上下文的情况。<private prefix>实际上是私有上下文的名称。URL的创建者和本地实体已配置为识别此名称，因此他们可以解释该号码并知道如何使用该号码。例如，专用网络编号计划可以用名称“X-COMPANY-NET”来表示，但是来自电话URL的发送者和本地实体的本地的专用拨号计划是不同的。这些标记的语法将留待将来的规范使用。上面的ABNF指定可作为<private prefix>一部分的接受字符。
Unless the sender is absolutely sure that they share the same private network access digit string with the local entity, then they MUST NOT use a dialling plan number (a local phone number, or one qualified by a local context), as the result may be incorrect. Instead, they SHOULD use a global number, or if that is not possible, a private context as the last resort. If the local entity does not support dialling into the private network indicated by that context, then the request MUST be rejected. If it does, then it will use the access digit string appropriate for its locale.
除非发送方完全确定他们与本地实体共享相同的专用网络访问数字字符串，否则他们不得使用拨号计划号码（本地电话号码或本地上下文限定的号码），因为结果可能不正确。相反，他们应该使用一个全局编号，或者如果不可能，则使用一个私有上下文作为最后手段。如果本地实体不支持拨入该上下文指示的专用网络，则必须拒绝该请求。如果是，则将使用适合其区域设置的访问数字字符串。
Note that the use of <area-specifier> is orthogonal to use of the telephony service provider parameter (see 2.5.10); it qualifies the phone number, whilst the <service-provider> parameter indicates the carrier to be used for the call attempt.
注意，<area specifier>的使用与电话服务提供商参数的使用是正交的（见2.5.10）；它限定了电话号码，而<service provider>参数指示用于呼叫尝试的运营商。
For example, a large company may have private network interconnections between its sites, as well as connections to the Global Switched Telephone Network. A phone number may be given in "public network" form, but with a <service-provider> indicating that the call should be carried over the corporate network.
例如，一家大公司可能在其站点之间有专用网络互连，以及与全球交换电话网络的连接。电话号码可以以“公共网络”的形式给出，但带有一个<service provider>，表示通话应通过公司网络进行。
Conversely, it would be possible to represent a phone number in private network form, with a private context to indicate this, but indicate a public telephony service provider. This would request that the user agent convert the private network number plan address into a form that can be carried using the selected service provider.
相反，可以用专用网络形式表示电话号码，并使用专用上下文来表示，但表示公共电话服务提供商。这将要求用户代理将专用网络号计划地址转换为可使用所选服务提供商携带的形式。
Any telephone number MUST contain at least one <phonedigit> or <dtmf-digit>, that is, subscriber numbers consisting only of pause characters are not allowed.
任何电话号码必须至少包含一个<phonedigit>或<dtmf digit>，即不允许仅包含暂停字符的用户号码。
International numbers MUST begin with the "+" character. Local numbers MUST NOT contain that character. International numbers MUST be written with the country (CC) and national (NSN) numbers as specified in [E.123] and [E.164]. International numbers have the property of being totally unambiguous everywhere in the world if the local entity is properly configured.
国际号码必须以“+”字符开头。本地数字不能包含该字符。国际编号必须与[E.123]和[E.164]中规定的国家（CC）和国家（NSN）编号一起书写。如果本地实体配置正确，国际数字在世界各地都具有完全明确的特性。
Local numbers MAY be used if the number only works from inside a certain geographical area or a network. Note that some numbers may work from several networks but not from the whole world - these SHOULD be written in international form, with a set of <area-specifier> tags and optional <service-provider> parameters. URLs containing local phone numbers should only appear in an environment where all local entities can get the call successfully set up by passing the number to the dialing entity "as is". An example could be a company intranet, where all local entities are located under a the same private telephone exchange. If local phone numbers are used,
如果本地号码仅在特定地理区域或网络内有效，则可以使用本地号码。请注意，一些数字可能来自多个网络，但不是来自全世界-这些数字应以国际形式书写，带有一组<area specifier>标记和可选的<service provider>参数。包含本地电话号码的URL只应出现在所有本地实体都可以通过“按原样”将号码传递给拨号实体来成功设置呼叫的环境中。例如，公司内部网，所有本地实体都位于同一个专用电话交换机下。如果使用本地电话号码，
the document in which they are present SHOULD contain an indication of the context in which they are intended to be used, and an appropriate <area-specifier> SHOULD be present in the URL.
它们所在的文档应包含它们拟在其中使用的上下文的指示，并且URL中应存在适当的<area specifier>。
In some regions, it is popular to write phone numbers using alphabetic characters which correspond to certain numbers on the telephone keypad. Letters in <dtmf-digit> characters do not have anything to do with this, nor is this method supported by these URL schemes.
在某些地区，使用与电话键盘上的某些数字相对应的字母字符书写电话号码是很流行的。<dtmf digit>字符中的字母与此无关，这些URL方案也不支持此方法。
It should also be noted that implementations MUST NOT assume that telephone numbers have a maximum, minimum or fixed length, or that they would always begin with a certain number. Implementors are encouraged to familiarize themselves with the international standards.
还应注意的是，实现不得假设电话号码具有最大、最小或固定长度，或者电话号码总是以某个号码开头。鼓励实施者熟悉国际标准。
All <visual-separator> characters MUST be ignored by the local entity when using the URL. These characters are present only to aid readability: they MUST NOT have any other meaning. Note that although [E.123] recommends the use of space (SP) characters as the separators in printed telephone numbers, spaces MUST NOT be used in phone numbers in URLs as the space character cannot be used in URLs without escaping it.
使用URL时，本地实体必须忽略所有<visual separator>字符。这些字符的出现只是为了帮助可读性：它们不能有任何其他含义。请注意，尽管[E.123]建议在打印的电话号码中使用空格（SP）字符作为分隔符，但在URL中的电话号码中不能使用空格，因为空格字符不能在URL中使用而不转义。
After the telephone number has been extracted, it can be converted to the local dialing convention. (For example, the "+" character might be replaced by the international call prefix, or the international and trunk prefixes might be removed to place a local call.) Numbers that have been specified using <local-phone> or <fax-local-phone> MUST be used by the local entity "as is", without any conversions, unless the local entity decides to utilize the information in an optional <service-provider> parameter.
提取电话号码后，可以将其转换为本地拨号约定。（例如，可以将“+”字符替换为国际呼叫前缀，或者删除国际和中继前缀以拨打本地呼叫。）使用<local phone>或<fax local phone>指定的号码必须由本地实体“按原样”使用，无需任何转换，除非本地实体决定使用可选的<service provider>参数中的信息。
The number may contain a <post-dial> sequence, which MUST be dialled using Dual Tone Multifrequency (DTMF) in-band signalling or pulse dialing after the call setup is complete. If the user agent does not support DTMF or pulse dialing after the call has been set up, <post-dial> MUST be ignored. In that case, the user SHOULD be notified.
该号码可能包含<post dial>序列，在呼叫设置完成后，必须使用双音多频（DTMF）带内信令或脉冲拨号进行拨号。如果用户代理在设置呼叫后不支持DTMF或脉冲拨号，<post dial>必须忽略。在这种情况下，应通知用户。
A local phone number or a post-dial sequence may contain <pause-character> characters which indicate a pause while dialing ("p"), or a wait for dial tone ("w").
本地电话号码或拨后序列可能包含<pause character>字符，表示拨号时暂停（“p”）或等待拨号音（“w”）。
Local entities MAY support this method of dialing, and the final interpretation of these characters is left to the local entity. It is RECOMMENDED that the length of each pause is about one second.
本地实体可能支持这种拨号方法，这些字符的最终解释权留给本地实体。建议每次暂停的长度约为1秒。
If it is not supported, local entities MUST ignore everything in the dial string after the first <pause-character> and the user SHOULD be notified. The user or the local entity MAY opt not to place a call if this feature is not supported and these characters are present in the URL.
如果不支持，本地实体必须忽略第一个<pause character>之后拨号字符串中的所有内容，并应通知用户。如果此功能不受支持且URL中存在这些字符，则用户或本地实体可能选择不拨打电话。
Any <dtmf-digit> characters and all dial string characters after the first <pause-character> or <dtmf-digit> SHOULD be sent to line using DTMF (Dual Tone Multifrequency) in-band signaling, even if dialing is done using direct network signaling (a digital subscriber loop or a mobile phone). If the local infrastructure does not support DTMF codes, the local entity MAY opt to use pulse dialing. However, it should be noted that certain services which are controlled using DTMF tones cannot be controlled with pulse dialing. If pulse dialing is used, the user SHOULD be notified.
任何<dtmf digit>字符和第一个<pause character>或<dtmf digit>之后的所有拨号字符串都应使用dtmf（双音多频）带内信令发送到线路，即使是使用直接网络信令（数字用户环路或移动电话）进行拨号。如果本地基础设施不支持DTMF代码，则本地实体可以选择使用脉冲拨号。但是，应注意，使用DTMF音调控制的某些服务不能通过脉冲拨号控制。如果使用脉冲拨号，应通知用户。
A phone number MAY also contain an <isdn-subaddress> which indicates an ISDN subaddress. The local entity SHOULD support ISDN subaddresses. These addresses are sent to the network by using a method available to the local entity (typically, ISDN subscribers send the address with the call setup signalling). If ISDN subaddressing is not supported by the caller, <isdn-subaddress> MUST be ignored and the user SHOULD be notified. The user or the local entity MAY opt not to place a call if this feature is not supported.
电话号码还可能包含表示isdn子地址的<isdn子地址>。本地实体应支持ISDN子地址。这些地址通过使用本地实体可用的方法发送到网络（通常，ISDN用户通过呼叫设置信令发送地址）。如果调用方不支持ISDN子地址，则必须忽略<ISDN子地址>，并通知用户。如果不支持此功能，用户或本地实体可能会选择不拨打电话。
A fax number MAY also contain a <t33-subaddress>, which indicates the start of a T.33 subaddress [T.33]. Local entities SHOULD support this. Otherwise <t33-subaddress> MUST be ignored and the user SHOULD be notified. The user or the local entity MAY opt not to place a call if this feature is not supported.
传真号码也可能包含<t33子地址>，表示T.33子地址[T.33]的开始。地方实体应支持这一点。否则必须忽略<t33子地址>，并通知用户。如果不支持此功能，用户或本地实体可能会选择不拨打电话。
<modem-params> indicate the minimum compliance required from the local entity to be able to connect to the remote entity. The minimum compliance is defined as being equal to or a superset of the capabilities of the listed modem type. There can be several <modem-param> parameters, in which case compliance to any one of them will be accepted. <recommended-params> indicates the recommended compliance required from the local entity. This is typically the fastest and/or the most reliable modem type supported by the modem pool. The local entity can use this information to select the best number from a group of modem URLs. There can be several recommended modem types, which are equally desirable from the modem pool's point of view. <recommended-params> MAY NOT conflict with <modem-params>. If they do, the local entity MUST ignore the <recommended-params>.
<modem params>表示本地实体连接到远程实体所需的最低合规性。最小符合性定义为等于所列调制解调器类型的功能或其超集。可以有多个<modem param>参数，在这种情况下，可以接受其中任何一个参数<建议参数>表示本地实体要求的建议符合性。这通常是调制解调器池支持的最快和/或最可靠的调制解调器类型。本地实体可以使用此信息从一组调制解调器URL中选择最佳号码。可以有几种推荐的调制解调器类型，从调制解调器池的角度来看，这些类型同样可取<建议的参数>可能与<modem params>不冲突。如果这样做，则本地实体必须忽略<recommended params>。
The local entity MUST call out using compatible hardware, or request that the network provides such a service.
本地实体必须使用兼容硬件呼叫，或请求网络提供此类服务。
For example, if the local entity only has access to a V.22bis modem and the URL indicates that the minimum acceptable connection is V.32bis, the local entity MUST NOT try to connect to the remote host since V.22bis is a subset of V.32bis. However, if the URL lists V.32 as the minimum acceptable connection, the local entity can use V.32bis to create a connection since V.32bis is a superset of V.32.
例如，如果本地实体只能访问V.22bis调制解调器，且URL指示最小可接受连接为V.32bis，则本地实体不得尝试连接到远程主机，因为V.22bis是V.32bis的子集。但是，如果URL将V.32列为可接受的最小连接，则本地实体可以使用V.32bis创建连接，因为V.32bis是V.32的超集。
This feature is present because modem pools often have separate numbers for slow modems and fast modems, or have different numbers for analog and ISDN connections, or may use proprietary modems that are incompatible with standards. It is somewhat analogous to the connection type specifier (typecode) in FTP URLs [RFC1738]: it provides the local entity with information that can not be deduced from the scheme specifier, but is helpful for successful operation.
之所以出现此功能，是因为调制解调器池通常对慢速调制解调器和快速调制解调器有单独的编号，或者对模拟和ISDN连接有不同的编号，或者可能使用与标准不兼容的专用调制解调器。它有点类似于FTP URL[RFC1738]中的连接类型说明符（typecode）：它为本地实体提供了无法从方案说明符推导出来的信息，但有助于成功操作。
This also means that the number of data and stop bits and parity MUST be set according to the information given in the URL, or to default values given in this document, if the information is not present.
这也意味着必须根据URL中给出的信息或本文档中给出的默认值（如果不存在该信息）设置数据和停止位的数量以及奇偶校验。
The capability tokens are listed below. If capabilities suggest that it is impossible to create a connection, the connection MUST NOT be created.
下面列出了功能令牌。如果功能表明无法创建连接，则不得创建连接。
If new modem types are standardized by ITU-T, this list can be extended with those capability tokens. Tokens are formed by taking the number of the standard and joining together the first letter (for example, "V"), number (for example, 22) and the first letter of the postfix (for example "bis" would become "b").
如果新的调制解调器类型由ITU-T标准化，则可使用这些功能令牌扩展此列表。代币是通过取标准的编号并将第一个字母（例如，“V”）、编号（例如，22）和后缀的第一个字母（例如，“bis”将变为“b”）连接在一起而形成的。
Proprietary modem types MUST be specified using the 'vendor naming tree', which takes the form "vnd.x.y", in which "x" is the name of the entity from which the specifications for the modem type can be acquired and "y" is the type or model of the modem. Vendor names MUST share the same name space with vendor names used in MIME types [RFC2048]. Submitting the modem types to ietf-types list for review is strongly recommended.
必须使用“供应商命名树”指定专有调制解调器类型，其形式为“vnd.x.y”，其中“x”是可从中获取调制解调器类型规范的实体名称，“y”是调制解调器的类型或型号。供应商名称必须与MIME类型[RFC2048]中使用的供应商名称共享相同的名称空间。强烈建议将调制解调器类型提交给ietf类型列表以供审查。
New capabilities MUST always be documented in an RFC, and they MUST refer to this document or a newer version of it. The documentation SHOULD also list the existing modem types with which the newly defined modem type is compatible with.
新功能必须始终记录在RFC中，并且必须参考本文档或其更新版本。文档还应列出新定义的调制解调器类型与之兼容的现有调制解调器类型。
Capability Explanation
能力解释
V21 ITU-T V.21 V22 ITU-T V.22 V22b ITU-T V.22bis V23 ITU-T V.23 V26t ITU-T V.26ter V32 ITU-T V.32 V32b ITU-T V.32bis V34 ITU-T V.34 V90 ITU-T V.90 V110 ITU-T V.110 V120 ITU-T V.120 X75 ITU-T X.75 B103 Bell 103 B212 Bell 212 Data bits: "8" or "7" The number of data bits. If not specified, defaults to "8". Parity: "n", "e", "o", Parity. None, even, odd, mark or "m", "s" space parity, respectively. If not specified, defaults to "n". Stop bits: "1" or "2" The number of stop bits. If not specified, defaults to "1".
V21 ITU-T V.21 V22 ITU-T V.22 V22b ITU-T V.22bis V23 ITU-T V.23 V26t ITU-T V.26ter V32 ITU-T V.32 V32b ITU-T V.32bis V34 ITU-T V.34 V90 V110 ITU-T V.110 V120 ITU-T V.120 X75 B103贝尔103 B212贝尔212数据位：“8”或“7”数据位数。如果未指定，则默认为“8”。奇偶性：“n”，“e”，“o”，奇偶性。无、偶数、奇数、标记或“m”、“s”空间奇偶校验。如果未指定，则默认为“n”。停止位：“1”或“2”停止位的数量。如果未指定，则默认为“1”。
It is possible to indicate the identity of the telephony service provider for the given phone number. <service-provider> MAY be used by the user-agent to place the call using this network, to enhance the user interface, for billing estimates or to otherwise optimize its functionality. It MAY also be ignored by the user-agent. <service-provider> consists of a fully qualified Internet domain name of the telephony service provider, for example ";tsp=terrifictelecom.com". The syntax of the domain name follows Internet domain name rules and is defined in [RFC1035].
可以指示给定电话号码的电话服务提供商的身份<用户代理可以使用服务提供商>来使用该网络进行呼叫、增强用户界面、进行计费估计或以其他方式优化其功能。它也可能被用户代理忽略<服务提供商>由电话服务提供商的完全限定的Internet域名组成，例如“tsp=terrimictelecom.com”。域名的语法遵循互联网域名规则，并在[RFC1035]中定义。
In addition to T.33 and ISDN subaddresses, modem types and area specifiers, future extensions to this URL scheme may add other additional parameters (<future-extension> in the BNF) to these URLs. These parameters are added to the URL after a semicolon (";"). Implementations MUST be prepared to handle additional and/or unknown parameters gracefully. Implementations MUST NOT use the URL if it contains unknown parameters, as they may be vital for the correct interpretation of the URL. Instead, the implementation SHOULD report an error.
除了T.33和ISDN子地址、调制解调器类型和区域说明符外，此URL方案的未来扩展可能会向这些URL添加其他参数（<future extension>）。这些参数添加到URL的分号（；）后。实现必须准备好优雅地处理附加和/或未知参数。如果URL包含未知参数，则实现不得使用URL，因为这些参数对于正确解释URL可能至关重要。相反，实现应该报告一个错误。
For example, <future-extension> can be used to store application-specific additional data about the phone number, its intended use, or any conversions that have been applied to the number. Whenever a <future-extension> is used in an open environment, its syntax and usage MUST be properly documented in an RFC.
例如，<future extension>可用于存储有关电话号码、其预期用途或已应用于该号码的任何转换的特定于应用程序的附加数据。无论何时在开放环境中使用<future extension>，其语法和用法都必须在RFC中正确记录。
<future-extension> nonterminal a rephrased version of, and compatible with the <other-param> as defined in [RFC2543] (which actually borrows BNF from an earlier version of this specification).
<future extension>nonterminal是[RFC2543]中定义的<other param>的重新表述版本，并与之兼容（实际上借用了本规范早期版本中的BNF）。
tel:+358-555-1234567
电话：+358-555-1234567
This URL points to a phone number in Finland capable of receiving voice calls. The hyphens are included to make the number more human-readable: country and area codes have been separated from the subscriber number.
此URL指向芬兰境内能够接收语音呼叫的电话号码。包括连字符是为了使号码更易于阅读：国家和地区代码与用户号码分开。
fax:+358.555.1234567
传真：+358.555.1234567
The above URL describes a phone number which can receive fax calls. It uses dots instead of hyphens as separators, but they have no effect on the functionality.
上面的URL描述了一个可以接收传真呼叫的电话号码。它使用点而不是连字符作为分隔符，但它们对功能没有影响。
modem:+3585551234567;type=v32b?7e1;type=v110
modem:+3585551234567;type=v32b?7e1;type=v110
This phone number belongs to an entity which is able to receive data calls. The local entity may opt to use either a ITU-T V.32bis modem (or a faster one, which is compatible with V.32bis), using settings of 7 data bits, even parity and one stop bit, or an ISDN connection using ITU-T V.110 protocol.
此电话号码属于能够接收数据呼叫的实体。本地实体可以选择使用ITU-T V.32bis调制解调器（或与V.32bis兼容的更快的调制解调器），使用7个数据位、偶数奇偶校验和一个停止位的设置，或者使用ITU-T V.110协议的ISDN连接。
tel:+358-555-1234567;postd=pp22
tel:+358-555-1234567;postd=pp22
The above URL instructs the local entity to place a voice call to +358-555-1234567, then wait for an implementation-dependent time (for example, two seconds) and emit two DTMF dialing tones "2" on the line (for example, to choose a particular extension number, or to invoke a particular service).
上述URL指示本地实体向+358-555-1234567进行语音呼叫，然后等待与实现相关的时间（例如，两秒），并在线路上发出两个DTMF拨号音“2”（例如，选择特定分机号码或调用特定服务）。
tel:0w003585551234567;phone-context=+3585551234
tel:0w003585551234567;phone-context=+3585551234
This URL places a voice call to the given number. The number format is intended for local use: the first zero opens an outside line, the "w" character waits for a second dial tone, and the number already has the international access code appended to it ("00"). This kind of phone number MUST NOT be used in an environment where all users of this URL might not be able to successfully dial out by using this number directly. However, this might be appropriate for pages in a company intranet. The <area-specifier> which is present hints that the number is usable only in an environment where the local entity's phone number starts with the given string (perhaps singling out a company-wide block of telephone numbers).
此URL向给定号码拨打语音电话。数字格式用于本地使用：第一个零打开外线，“w”字符等待第二个拨号音，“w”字符已经附加了国际访问码（“00”）。如果此URL的所有用户可能无法直接使用此号码成功拨出，则不得在这种环境中使用此类电话号码。但是，这可能适用于公司内部网中的页面。出现的<area specifier>提示该号码仅在本地实体的电话号码以给定字符串开头的环境中可用（可能会挑出公司范围内的电话号码块）。
tel:+1234567890;phone-context=+1234;vnd.company.option=foo
tel:+1234567890;phone-context=+1234;vnd.company.option=foo
The URL describes a phone number which, even if it is written in its international form, is only usable within the numbering area where phone numbers start with +1234. There is also a proprietary extension "vnd.company.option", which has the value "foo". The meaning of this extension is application-specific. Note that the order of these parameters (phone-context and vnd.company.option) is irrelevant.
URL描述的电话号码即使是以国际形式书写的，也只能在电话号码以+1234开头的编号区域内使用。还有一个专有扩展“vnd.company.option”，其值为“foo”。此扩展的含义是特定于应用程序的。请注意，这些参数（电话上下文和vnd.company.option）的顺序是不相关的。
URLs locate resources, which in this case is some telecommunications equipment at a given phone number. However, it is not necessarily enough to know the subscriber number in order to successfully communicate with that equipment. Digital phone networks distinguish between voice, fax and data calls (and possibly other types of calls, not discussed in this specification). To be able to successfully connect to, say, a fax machine, the caller may have to specify that a fax call is being made. Otherwise the call might be routed to the voice number of the subscriber. In this sense, the call type is an integral part of the 'location' of the target resource.
URL定位资源，在本例中是给定电话号码处的一些电信设备。然而，为了成功地与该设备通信，知道用户号码并不一定足够。数字电话网络区分语音、传真和数据呼叫（以及本规范中未讨论的其他类型的呼叫）。为了能够成功地连接到（比如）传真机，呼叫者可能必须指定正在进行传真呼叫。否则，呼叫可能会被路由到用户的语音号码。从这个意义上说，调用类型是目标资源“位置”的一个组成部分。
The reason to have the call type in the scheme specifier is to make the URL simple to remember and use. Making it a parameter, much like the way modem parameters are handled now, will substantially reduce the human readability of this URL.
在scheme说明符中使用调用类型的原因是为了使URL易于记住和使用。将其作为参数，就像现在处理调制解调器参数的方式一样，将大大降低此URL的可读性。
There has been discussion on whether the scheme name "tel" is appropriate. To summarize, these are the points made against the other proposals.
关于方案名称“tel”是否合适的问题，已经进行了讨论。总而言之，这些是针对其他提案提出的观点。
callto URL schemes locate a resource and do not specify an action to be taken. telephone Too long. Also, "tel" considered to be a more international form. phone Was countered on the basis that "tel" is more internationally acceptable.
CallToURL方案定位资源，不指定要执行的操作。电话太长了。此外，“电话”被认为是一种更国际化的形式。该电话遭到反击，理由是“电话”更为国际接受。
E.164 refers to international telephone numbers, and the string of digits after the country code is usually a national matter. In any case, phone numbers are usually written as a simple string of numbers everywhere. Because of this, the syntax in this specification is intuitively clear to most people. This is the usual way to write phone numbers in business cards, advertisements, telephone books and so on.
E.164指国际电话号码，国家代码后的数字串通常是国家事务。在任何情况下，电话号码通常都被写成一个简单的数字串。因此，本规范中的语法对大多数人来说是直观的。这是在名片、广告、电话簿等上写电话号码的常用方法。
It should be noted that phone numbers may have 'hierarchical' characteristics, so that one could build a 'forest' of phone numbers with country codes as roots, area codes as branches and subscriber numbers as leaves. However, this is not always the case. Not all areas have area codes; some areas may have different area codes depending on how one wants to route the call; some numbers must always be dialled "as is", without prepending area or country codes (notably emergency numbers); and area codes can and do change.
需要注意的是，电话号码可能具有“层次”特征，因此可以建立电话号码的“森林”，以国家代码为根，区号为分支，用户号码为叶。然而，情况并非总是如此。并非所有区域都有区号；一些地区可能有不同的区号，这取决于人们想如何路由呼叫；某些号码必须始终按“原样”拨号，不预先输入地区或国家代码（尤其是紧急号码）；区号也会改变。
Usually, if something has a hierarchical structure, the URL syntax should reflect that fact. These URLs are an exception.
通常，如果某事物具有层次结构，URL语法应该反映这一事实。这些URL是一个例外。
Also, when writing the phone number in the form described in this specification, the writer does not need to know which part of the number is the country code and which part is the area code. If a hierarchical URL would be used (with a "/" character separating the parts of the phone numbers), the writer of the URL would have to know which parts are which.
此外，当以本规范中描述的形式书写电话号码时，书写者不需要知道号码的哪部分是国家代码，哪部分是区号。如果要使用分层URL（电话号码的各个部分之间用“/”字符分隔），则URL的编写者必须知道哪些部分是哪些部分。
Finally, when phone numbers are written in the international form as specified here, they are unambiguous and can always be converted to the local dialing convention, given that the user agent has the knowledge of the local country and area codes.
最后，当电话号码以此处指定的国际形式书写时，它们是明确的，并且始终可以转换为本地拨号约定，因为用户代理知道本地国家和地区代码。
There are several ways for the subscriber to dial a phone number:
用户拨打电话号码有几种方式：
- By pulse dialing. Typically old telephone exchanges. Usually this dialing method has only to be used to set up the call; after connecting to the remote entity, <post-dial> can be sent to the line using DTMF, because it will typically be processed by the remote entity, not the telephone network.
- 通过脉冲拨号。典型的老式电话交换机。通常，这种拨号方法只用于建立呼叫；连接到远程实体后，可以使用DTMF将<post dial>发送到线路，因为它通常由远程实体处理，而不是电话网络。
- By DTMF. These are the 'beeps' that you hear when you dial on most phones.
- 通过双音多频。这些是你在大多数电话上拨号时听到的“嘟嘟声”。
- By direct network signalling. ISDN subscribers and mobile phone users usually have this. There is no dial tone (or if there is, it is generated locally by the equipment), and the number of the called party is communicated to the telephone network using some network signalling method. After setting up the call, <post-dial> sequences are usually sent using DTMF codes.
- 通过直接网络信令。ISDN用户和移动电话用户通常都有这个功能。没有拨号音（如果有，则由设备本地生成），被叫方的号码通过某种网络信令方法传送到电话网络。设置呼叫后，<post dial>序列通常使用DTMF代码发送。
As an example, +123456789 will be dialled in many countries as 00123456789, where the leading "00" is a prefix for international calls. However, if a URL contains a local phone number 00123456789, the user-agent MUST NOT assume that this number is equal to a global phone number +123456789. If a user-agent received a telephony URL with a local number in it, it MUST make sure that it knows the context in which the local phone number is to be processed, or else the number MUST NOT be used. Equally, anyone sending a telephony URL MUST take into consideration that the recipient may have insufficient information about the phone number's context.
例如，+123456789将在许多国家拨打00123456789，其中前导“00”是国际长途的前缀。但是，如果URL包含本地电话号码00123456789，则用户代理不得假定此号码等于全局电话号码+123456789。如果用户代理收到带有本地号码的电话URL，则必须确保它知道本地电话号码要处理的上下文，否则不得使用该号码。同样，任何发送电话URL的人都必须考虑到收件人可能没有足够的电话号码上下文信息。
These are examples of the recommended usage of this URL in HTML documents.
以下是建议在HTML文档中使用此URL的示例。
First of all, the number SHOULD be visible to the end user, if it is conceivable that the user might not have a local entity which is able to use these URLs.
首先，如果用户可能没有能够使用这些URL的本地实体，那么最终用户应该可以看到该号码。
Telephone: <a href="tel:+3585551234567">+358-555-1234567</a>
Telephone: <a href="tel:+3585551234567">+358-555-1234567</a>
Second, on a public HTML page, the telephone number in the URL SHOULD always be in the international form, even if the text of the link uses some local format.
其次，在公共HTML页面上，URL中的电话号码应始终采用国际格式，即使链接的文本使用某些本地格式。
Telephone: <a href="tel:+3585551234567">(0555) 1234567</a>
Telephone: <a href="tel:+3585551234567">(0555) 1234567</a>
or even
甚至
For more info, call <a href="tel:+15554383785965">1-555-IETF-RULZ-OK</a>.
有关更多信息，请致电<a href=“电话：+15554383785965”>1-555-IETF-RULZ-OK</a>。
Moreover, if the number is a <local-phone-number>, and the scope of the number is not clear from the context in which the URL is displayed, a human-readable explanation SHOULD be included.
此外，如果号码是<本地电话号码>，并且该号码的范围与显示URL的上下文不清楚，则应包括可读的说明。
For customer service, dial <a href="tel:1234;phone-context=+358555">1234</a> (only from Terrific Telecom mobile phones).
对于客户服务，请拨打1234（仅适用于绝妙的电信移动电话）。
[RFC1035] Mockapetris, P., "Domain Names - Implementation and Specification", STD 13, RFC 1035, November 1987.
[RFC1035]Mockapetris，P.，“域名-实现和规范”，STD 13，RFC 1035，1987年11月。
[RFC1738] Berners-Lee, T., et al., "Uniform Resource Locators (URL)", RFC 1738, December 1994.
[RFC1738]Berners Lee，T.等人，“统一资源定位器（URL）”，RFC 17381994年12月。
[RFC1866] Berners-Lee, T. and D. Connolly, "Hypertext Markup Language - 2.0", RFC 1866, November 1995.
[RFC1866]Berners Lee，T.和D.Connolly，“超文本标记语言-2.0”，RFC 18661995年11月。
[RFC2048] Freed, N., Klensin, J. and J. Postel, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", RFC 2048, November 1996.
[RFC2048]Freed，N.，Klensin，J.和J.Postel，“多用途互联网邮件扩展（MIME）第四部分：注册程序”，RFC 20481996年11月。
[RFC2119] Bradner, S., "Key Words for Use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，1997年3月。
[RFC2234] Crocker, D. and P. Overall, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997.
[RFC2234]Crocker，D.和P.总体，“语法规范的扩充BNF:ABNF”，RFC 2234，1997年11月。
[RFC2303] Allocchio, C., "Minimal PSTN Address Format in Internet Mail", RFC 2303, March 1998.
[RFC2303]Allocchio，C.，“互联网邮件中的最小PSTN地址格式”，RFC2303，1998年3月。
[RFC2304] Allocchio, C., "Minimal FAX Address Format in Internet Mail", RFC 2304, March 1998.
[RFC2304]Allocchio，C.，“互联网邮件中的最小传真地址格式”，RFC2304，1998年3月。
[RFC2396] Berners-Lee, T., R. Fielding and L. Manister, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998.
[RFC2396]Berners Lee，T.，R.Fielding和L.Manister，“统一资源标识符（URI）：通用语法”，RFC 2396，1998年8月。
[RFC2543] Handley, M., Schulzrinne, H., Schooler, E. and J. Rosenberg, "SIP: Session Initiation Protocol", RFC 2543, March 1999.
[RFC2543]Handley，M.，Schulzrinne，H.，Schooler，E.和J.Rosenberg，“SIP：会话启动协议”，RFC 25431999年3月。
[E.123] ITU-T Recommendation E.123: Telephone Network and ISDN Operation, Numbering, Routing and Mobile Service: Notation for National and International Telephone Numbers. 1993.
[E.123]ITU-T建议E.123：电话网络和ISDN操作、编号、路由和移动服务：国家和国际电话号码的符号。1993
[E.164] ITU-T Recommendation E.164/I.331 (05/97): The International Public Telecommunication Numbering Plan. 1997.
[E.164]ITU-T建议E.164/I.331（05/97）：国际公共电信编号计划。1997
[T.33] ITU-T Recommendation T.33: Facsimile Routing Utilizing the Subaddress. 1996.
[T.33]ITU-T建议T.33：利用子地址的传真路由。1996
It should be noted that the local entity SHOULD NOT call out without the knowledge of the user because of associated risks, which include
应注意的是，由于相关风险，本地实体不应在用户不知情的情况下呼叫，包括
- call costs (including long calls, long distance calls, international calls and premium rate calls, or calls which do not terminate due to <post-dial> sequences that have been left out by the local entity)
- 通话费用（包括长途电话、长途电话、国际电话和特价电话，或由于本地实体遗漏了<post dial>序列而未终止的电话）
- wrong numbers inserted on web pages by malicious users, or sent via e-mail, perhaps in direct advertising
- 恶意用户在网页上插入的错误号码，或通过电子邮件发送的错误号码，可能是在直接广告中
- making the user's phone line unavailable (off-hook) for a malicious purpose
- 出于恶意目的使用户的电话线不可用（脱离连接）
- opening a data call to a remote host, thus possibly opening a back door to the user's computer
- 打开对远程主机的数据调用，从而可能打开用户计算机的后门
- revealing the user's (possibly unlisted) phone number to the remote host in the caller identification data, and correlating the local entity's phone number with other information such as the e-mail or IP address
- 在呼叫者标识数据中向远程主机显示用户（可能未列出）的电话号码，并将本地实体的电话号码与其他信息（如电子邮件或IP地址）关联
- using the same local number in different contexts, in which the number may have a different meaning
- 在不同的上下文中使用相同的本地数字，其中数字可能具有不同的含义
All of these risks MUST be taken into consideration when designing the local entity.
在设计本地实体时，必须考虑所有这些风险。
The local entity SHOULD have some mechanism that the user can use to filter out unwanted numbers. The local entity SHOULD NOT use rapid redialing of the number if it is busy to avoid the congestion of the (signaling) network. Also, the local entity SHOULD detect if the number is unavailable or if the call is terminated before the dialing string has been completely processed (for example, the call is terminated while waiting for user input) and not try to call again, unless instructed by the user.
本地实体应该有一些机制，用户可以使用这些机制过滤掉不需要的数字。如果本地实体正忙，则不应使用快速重拨号码，以避免（信令）网络拥塞。此外，本地实体应检测号码是否不可用，或者在拨号字符串完全处理之前是否终止呼叫（例如，在等待用户输入时终止呼叫），并且除非用户指示，否则不得再次尝试呼叫。
Writing this specification would not have been possible without extensive support from many people.
如果没有许多人的广泛支持，编写此规范是不可能的。
Contributors include numerous people from IETF FAX, PINT, URI and URLREG mailing lists, as well as from World Wide Web Consortium and several companies, plus several individuals. Thanks to all people who offered criticism, corrections and feedback.
贡献者包括来自IETF传真、PINT、URI和URLREG邮件列表的许多人，以及来自万维网联盟和多家公司的许多人，以及一些个人。感谢所有提出批评、纠正和反馈的人。
All phone numbers and company names used in the examples of this specification are fictional. Any similarities to real entities are coincidental.
本规范示例中使用的所有电话号码和公司名称都是虚构的。与真实实体的任何相似之处都是巧合。
Antti Vaha-Sipila (quoted-printable: Antti V=E4h=E4-Sipil=E4) Nokia Mobile Phones P. O. Box 68 FIN-33721 Tampere Finland
Antti Vaha Sipila（引用可打印：Antti V=E4h=E4 Sipil=E4）诺基亚手机邮政信箱68 FIN-33721坦佩雷芬兰
EMail: avs@iki.fi
antti.vaha-sipila@nokia.com
EMail: avs@iki.fi
antti.vaha-sipila@nokia.com
Copyright (C) The Internet Society (2000). All Rights Reserved.
版权所有（C）互联网协会（2000年）。版权所有。
This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English.
本文件及其译本可复制并提供给他人，对其进行评论或解释或协助其实施的衍生作品可全部或部分编制、复制、出版和分发，不受任何限制，前提是上述版权声明和本段包含在所有此类副本和衍生作品中。但是，不得以任何方式修改本文件本身，例如删除版权通知或对互联网协会或其他互联网组织的引用，除非出于制定互联网标准的需要，在这种情况下，必须遵循互联网标准过程中定义的版权程序，或根据需要将其翻译成英语以外的其他语言。
The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns.
上述授予的有限许可是永久性的，互联网协会或其继承人或受让人不会撤销。
This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
本文件和其中包含的信息是按“原样”提供的，互联网协会和互联网工程任务组否认所有明示或暗示的保证，包括但不限于任何保证，即使用本文中的信息不会侵犯任何权利，或对适销性或特定用途适用性的任何默示保证。
Acknowledgement
确认
Funding for the RFC Editor function is currently provided by the Internet Society.
RFC编辑功能的资金目前由互联网协会提供。