Rec. No.
INTRODUCTION
SECTION 1 –
Functional description of the
signalling system
Q.251 1.1 General
Q.252 1.2 Signal transfer time
definitions
Q.253 1.3 Association between
signalling and speech networks
SECTION 2 – Definition and function of signals
Q.254
2.1 Telephone signals
Q.255 2.2 Signalling-system-control
signals
Q.256 2.3 Management signals
SECTION 3 –
Signal unit formats and codes
Q.257 3.1 General
Q.258 3.2 Telephone signals
Q.259
3.3 Signalling-system-control
signals
Q.260 3.4 Management signals
SECTION 4 – Signalling procedures
Q.261 4.1 Normal
call set-up
Q.262 4.2 Analysis of digital
information for routing
Q.263 4.3 Double seizing with
both-way operation
Q.264 4.4 Potential for
automatic repeat attempt and re-routing
Q.265 4.5 Speed of switching
and signal transfer in international exchanges
Q.266 4.6
Blocking and
unblocking sequences and control of quasi-associated signalling
Q.267
4.7 Unreasonable and
superfluous messages 46
Q.268
4.8 Release of
international connections and associated equipment
SECTION 5 – Continuity check of the speech path
Q.271 5.1 General
5.2 Reliability of the speech path across the
exchange
5.3 Continuity check of the speech circuit between exchanges
5.4 Loop checking method
5.5 Transmission requirements for the continuity check
5.6 Continuity
signal
5.7 Timing considerations for the continuity check
SECTION 6 –
Signalling link
Q.272 6.1 Requirements for the
signalling data link
Q.273 6.2 Data transmission
rate
Q.274 6.3 Transmission methods
6.4 Modem and interface requirements
Q.275 6.5 Data channel failure
detection
Q.276 6.6 Service dependability
Q.277
6.7 Error control
Q.278 6.8 Synchronization
Q.279
6.9 Drift
compensation
SECTION
7 – Signal traffic
characteristics
Q.285 7.1 Signal priority
categories
Q.286 7.2 Signalling channel
loading and queueing delays
Q.287 7.3 Signal transfer time
requirements
SECTION 8 – Security arrangements
Q.291 8.1General
8.2 Basic security arrangements
8.3 Types of failure, recognition of failure and abnormal error rates
Q.292
8.4 Reserve facilities
provided
Q.293 8.5 Intervals at which
security measures are to be invoked
8.6 Changeover and changeback procedures
8.7 Emergency restart procedure
8.8 Full-time synchronized reserve links
8.9 Load sharing method
SECTION 9 – Testing and maintenance
Q.295 9.1 Overall tests of
Signalling System No. 6
9.2 Signalling data link
9.3 (Reserved)
9.4 (Reserved)
9.5 Network maintenance
Q.296 9.6 Monitoring
and maintenance of the common signalling channel
SECTION 10 – Network management
Q.297 10 Network management
10.1 General
10.2
Information categories
Annex –
The application of network management signals transported by System No. 6
Annex A to Signalling System No. 6 specifications
Annex B to Signalling System No. 6
specifications