📄 7_3_03.txt
字号:
5i'
Recommendation T.30
PROCEDURES FOR DOCUMENT FACSIMILE TRANSMISSION
IN THE GENERAL SWITCHED TELEPHONE NETWORK
(former Recommendation T.4, Mar del Plata, 1968;
amended and renumbered at Geneva, 1976 and 1980,
Malaga-Torremolinos, 1984 and Melbourne, 1988)
Introduction
i) This Recommendation is intended to apply to document fac-
simile apparatus covered by CCITT Recommendations T.2, T.3 and T.4.
It describes the procedures and signals to be used where facsimile
equipments are operated over the general switched telephone net-
work. When existing equipments are operating in a non-CCITT manner,
they shall not interfere with equipments operating in accordance
with the Series T Recommendations.
ii) Arrangements for automatic calling/answering on the gen-
eral switched telephone network have been aligned as closely as
possible with those described in the Series V Recommendations for
data terminal equipment.
iii) While there are eight possible operating methods (see
Table 1/T.30) each may be described by five separate and consecu-
tive phases:
Phase A Call set up
Phase B Pre-message procedure for identifying and select-
ing the required facilities
Phase C Message transmission (includes phasing and
synchronization where appropriate)
Phase D Post-message procedure including
end-of-message and confirmation and multi-document procedures
Phase E Call release
_________________________
Facsimile apparatus referred to as Groups 1, 2 or 3 in
this Recommendation are those cnforming to
Recommendations T.2, T.3 or T.4 respectively.
iv) Two separate signalling systems are described: first a
simple system using single frequency tones and second a binary
coded system which offers a wide range of signals for more complex
operational procedures. Thus tonal signalling is restricted to
manual operation at both stations or where a manually operated sta-
tion intends to transmit to a called station equipped as an
automatic answering receiver conforming to Recommendations T.2
and T.3 will normally use the tonal signalling system although the
binary coded system may be provided in addition where complex pro-
cedures are required, e.g. comprehensive automatic functions.
v) For digital document facsimile apparatus conforming to
Recommendation T.4 it is intended that the binary coded system
shall be the standard signalling arrangement, but additionally a
tonal signalling capability may be provided when the digital fac-
simile apparatus has a fallback capability to apparatus conforming
to Recommendations T.2 and T.3. The binary coded signalling has
priority and should be tried first; if this fails to elicit a
response, tonal signalling should be attempted.
vi) The binary coded signalling system is based on a high
level data link control (HDLC) format developed for data transmis-
sion procedures. The basic HDLC structure consists of a number of
frames each of which is subdivided into a number of fields. It pro-
vides for frame labelling , error checking and confirmation of
correctly received information and the frames can be easily
extended if this should be required in the future.
vii) The transmission of the facsimile message itself (phase
C) will be according to the modulation system described in the
appropriate Recommendation for the facsimile apparatus.
CONTENTS
1 Scope
2 Explanation of terms used
3 Description of a facsimile call
4 Tonal signalling for facsimile procedure
5 Binary coded signalling for facsimile procedure
Annex A - Procedure for Group 3 document facsimile
transmission in the general switched telephone network incorporat-
ing error correction
Appendix I - Example of non-standard manual-to-manual
basic facsimile operation
Appendix II - Index of abbreviations used in
Recommendation T.30
Appendix III - List of commands and appropriate
responses
Appendix IV - Interworking between the standard mode
and the recognized optional mode for the binary coded handshaking
procedure
Appendix V - Signal sequence examples
The CCITT,
considering
(a) that facilities exist for facsimile transmission over the
general switched telephone network;
(b) that such facsimile transmission may be requested either
alternatively with telephone conversation or when either or both
stations are not attended;
(c) that for this reason the operations involved in establish-
ing and/or releasing a facsimile call should be capable of
automatic operation;
unanimously declares the view
that the facsimile apparatus should be designed and operated
according to the following standards:
1 Scope
1.1 General
1.1.1 This Recommendation is concerned with the procedures
which are necessary for document transmission between two facsimile
stations in the general switched telephone network.
These procedures essentially comprise the following:
- call establishment and call release,
- compatibility checking , status and control com-
mand ,
- checking and supervision of line conditions ,
- control functions and facsimile operator recall
1.1.2 Only the procedures with their corresponding signals are
specified in this Recommendation.
1.2 Classification of operating methods
1.2.1 This Recommendation regulates the operational sequence
of manually operated facsimile stations as well as of automatic
stations.
The automatic facsimile station is understood to be a station
which is capable of performing all procedures (listed in S
1.1 above) automatically. In this case, an operator is not neces-
sary.
If, however, an operator is required for any of these pro-
cedures, the station must be regarded as a manually operated sta-
tion.
1.2.2 Based upon all combinations which may result from the
fact that there are manually operated stations and automatic fac-
simile stations, the operating methods shown in Table 1/T.30 are
possible.
H.T. [T1.30]
TABLE 1/T.30
_________________________________________________________________________________
Method No. {
Description of operating method
} {
Direction of facsimile transmission
} Overall designation
_________________________________________________________________________________
{
{
1-T
{
{
1
1-R
_________________________________________________________________________________
{
{
2-T
{
{
2
2-R
_________________________________________________________________________________
{
{
3-T
{
{
3
3-R
_________________________________________________________________________________
{
{
4-T
{
{
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -