1 General
1.1 Scope
1.2 References
1.3 Definitions
1.4 Abbreviations
2 Basic call control and signalling
procedures
2.1 Successful call set‑up
2.1.1 Forward address signalling – En
bloc operation
2.1.2 Forward address signalling – Overlap operation
2.1.3 Calling party number
2.1.4 Address complete message or connect message
2.1.5 Call progress (Basic call)
2.1.6 Information messages
2.1.7 Answer message
2.1.8 Continuity‑check
2.1.9 Charging
2.1.10 Forward transfer message
2.1.11 Transit network selection (national use)
2.1.12 Simple segmentation
2.1.13 Procedure for N × 64 kbit/s connection type
2.2 Unsuccessful call set‑up
2.2.1 Actions at exchange initiating a release message
2.2.2 Actions at intermediate exchange
2.2.3 Actions at the controlling exchange (i.e. the exchange controlling the
call)
2.2.4 Tones and announcements
2.2.5 Address incomplete
2.3 Normal call release
2.3.1 Release initiated by a calling party
2.3.2 Release initiated by a called party
2.3.3 Release initiated by the network
2.3.4 Storage and release of initial address message information
2.3.5 Pre-release information transport
2.4 Suspend, resume
2.4.1 Suspend
2.4.2 Resume
2.4.3 Expiration of timer (T6) or timer (T38)
2.5 Signalling procedures for
connection type allowing fallback
2.5.1 Actions in the forward direction
2.5.2 Actions in the backward direction – fallback
indicated before answer
2.5.3 Actions in the backward direction – fallback indicated at answer
2.5.4 Actions in the backward direction – fallback does not occur
2.6 Propagation delay determination
procedure
2.6.1 Procedure
2.7 Echo control signalling procedures
2.7.1 Introduction
2.7.2 Enhanced echo control signalling procedures
2.7.3 Simple echo control signalling procedures
2.7.4 Interworking considerations
2.8 Network features
2.8.1 Automatic repeat attempt
2.8.2 Blocking and unblocking of circuits and circuit groups
2.8.3 Circuit group query (national use)
2.9 Abnormal conditions
2.9.1 Dual seizure
2.9.2 Transmission alarm handling for digital inter-exchange circuits
2.9.3 Reset of circuits and circuit groups
2.9.4 Failure in the blocking/unblocking sequence
2.9.5 Receipt of unreasonable signalling information messages
2.9.6 Failure to receive a "release
complete" message – Timer T1 and T5
2.9.7 Failure to receive a response to an information request message
(national use)
2.9.8 Other failure conditions
2.9.9 Temporary Trunk Blocking (TTB) (national use)
2.10 ISDN user part signalling
congestion control
2.10.1 General
2.10.2 Procedures
2.11 Automatic congestion control
2.11.1 Receipt of a release message containing an
automatic congestion level parameter
2.11.2 Actions taken during overload
2.12 Unequipped circuit identification
code message (national use)
2.13 ISDN user part availability
control
2.13.1 General
2.13.2 Procedures
2.14 MTP pause/resume
2.15 Overlength messages
2.16 Support for Temporary Alternative
Routing (TAR)
2.17 Hop counter procedure
2.17.1 Actions at the initiating exchange
2.17.2 Actions at an intermediate exchange
2.17.3 Actions at the destination local exchange
2.18 Call collect request procedure
2.19 Support for hard to reach network
management functions
2.19.1 Exchange initiating HTR indication
2.19.2 Exchange receiving HTR indication
2.20 Calling geodetic location
procedure
2.20.1 Introduction
2.20.2 Transfer of geodetic information
Annex A
Annex B – Figures on basic call control signalling
procedures
Annex C – Examples of echo control signalling
procedures
C.0 Interworking model
C.1 Basic call set-up for the case
where all exchanges support the enhanced echo control signalling procedures,
and have echo control equipment available
C.2 Call set-up incorporating multiple
forwarding for the case where all exchanges support the enhanced echo control
signalling procedures, and echo control equipment is not available in all
exchanges
C.3 Basic call set-up for the case
where all exchanges support the enhanced echo control signalling procedures,
and echo control equipment is not available in all exchanges
C.4 Interworking with signalling
systems in the preceding network that do not support the enhanced echo control
logic control signalling procedures
C.4.1 Interworking from the simple echo control signalling procedures
C.4.2 Interworking from ITU-T Q.764 (1992 version)
C.5 Interworking with signalling
systems in the succeeding network that do not support the enhanced echo control
logic signalling procedures
C.5.1 Interworking to the simple echo control signalling procedures
C.5.2 Interworking to ITU-T Q.764 (1992 version)
C.6 Interworking between an exchange
supporting the simple echo control signalling procedures and ITU-T Q.764 (1992
version)
C.6.1 Interworking from an exchange supporting the simple echo control
signalling procedures to ITU-T Q.764 (1992 version)
C.6.2 Interworking from an exchange using ITU-T Q.764 (1992 version) to an
exchange supporting the simple echo control signalling procedures
C.7 Exchanges supporting the enhanced
echo control signalling procedures interacting with intelligent network
entities
Annex D – Examples of signalling procedures for
connection type allowing fallback
Annex E – Test calls
E.1 Called number for test calls
E.2 Accounting of test calls
Annex F – Cause values
Annex G – Start up procedures
G.1 Initial procedure for putting the
first group of circuits into service
G.2 Initial procedure for putting
additional circuits into service
G.3 Test procedures