ANNEX A (to Recommendation Q.764) Timers used in Recommendation Q.764 (Sheet 1 of 6) Symbol Time-out Cause for Normal At the first At the following value Significanc initiation termination expiry expiry e T1 4-15 s Local When release At the receipt of Retransmit Same as the first message is sent release complete release message expiry message and reinitialize timer T1 T2 3 min Dual When At the receipt of Initiate - controlling resume (user) release exchange message at procedure receives suspend controlling (user) message exchange T3 3 min Dual When local When hold Initiate - exchange sends condition is release delayed release removed procedure message T4 4-15 s Dual When local Fascicle VI.8 - Rec. Q.764 PAGE1 exchange sends At the reception - call call modification modification complete message request message T5 1 min Local When initial At receipt of Send reset The sending of release message release complete circuit message, the de reset is sent message alert circuit message maintenance should continue at personnel, and 1-min intervals remove the until maintenance circuit from intervention service occurs T6 Covered in Dual When At the receipt of Initiate - Q.118 controlling resume (network) release exchange message procedure receives suspend (network) PAGE6 Fascicle VI.8 - Rec. Q.764 Timers used in Recommendation Q.764 (Sheet 2 of 6) Symbol Time-out Cause for Normal At the first At the following value Significanc initiation termination expiry expiry e T7 20-30 s Dual When the latest When the Release all - address message condition for equipment and is sent normal release of connection (Send address and release message) routing informations is met (receipt of ACM, CON, messages) T8 10-15 s Local When transit of At receipt of Release all - incoming continuity message equipment and international connection into exchange national network receives initial (Send release adress message message) T9 Interval Dual When national At the receipt of Release - specified controlling or answer connection send in Q.118 outgoing back release international message exchange sends latest address message after the receipt of ACM T10 4-6 s Dual When last digit Fascicle VI.8 - Rec. Q.764 PAGE1 is received in At the receipt of Send address - interworking fresh information complete message situations T11 15-20 s Dual When latest Send ACM Send address - address message complete message is received in interworking situations PAGE6 Fascicle VI.8 - Rec. Q.764 Timers used in Recommendation Q.764 (Sheet 3 of 6) Symbol Time-out Cause for Normal At the first At the following value Significanc initiation termination expiry expiry e T12 4-15 s Local When blocking At receipt of Retransmit Same as the left message is sent blocking blocking message until T13 expires acknowledgement and initiate T12 T13 1 min Local When initial At receipt of Retransmit The reception of blocking message blocking blocking message message should be is sent acknowledgement and alert continued until maintenance maintenance personnel and intervention start T13. Stop occurs and circuit T12 taken out of service as appropriate T14 4-15 s Local When unblocking At receipt of Retransmit Same as the left message is sent unblocking unblocking until T15 expires acknowledgement message and initiate T14 timer T15 1 min Local When initial Fascicle VI.8 - Rec. Q.764 PAGE1 unblocking At receipt of Retransmit The repetition of message is sent unblocking unblocking message should be acknowledgement message alert continued until maintenance maintenance personnel, start intervention T15 timer and occurs and circuit stop T14 taken out of service as appropriate T16 4-15 s Local When reset At the receipt of Retransmit Same as the left circuit message the reset circuit until T17 expires is sent acknowledgement message and (RLC message) restart T16 T17 1 min Local When initial At receipt of the Alert The repetition of reset circuit acknowledgement maintenance message should be message is sent personnel continued until retransmit reset maintenance circuit message, intervention restart T17 and occurs stop T16 PAGE6 Fascicle VI.8 - Rec. Q.764 Timers used in Recommendation Q.764 (Sheet 4 of 6) Symbol Time-out Cause for Normal At the first At the following value Significanc initiation termination expiry expiry e T18 4-15 s Local When group At receipt of Retransmit Same as the left blocking message group blocking group blocking until T18 expires is sent acknowledgement message and initiate T18 T19 1 min Local When initial At receipt of Retransmit The repetition of group blocking group blocking group blocking message should be message is sent acknowledgement message, alert continued until maintenance maintenance personnel, intervention initiate T19 and occurs and stop T18 circuits taken out of service as appropriate T20 4-15 s Local When group At receipt of Retransmit Same as the left unblocking group unblocking group unblocking until T20 expires message is sent acknowledgement message and initiate T20 T21 1 min Local When initial Fascicle VI.8 - Rec. Q.764 PAGE1 group unblocking At receipt of Retransmit The repetition of message is sent group unblocking group unblocking message should be acknowledgement message, alert continued until maintenance maintenance personnel, intervention initiate T21 and occurs and stop T20 circuits taken out of service as appropriate T22 4-15 s Local When circuit At the receipt of Retransmit Same as the first group reset the circuit group expiry until T23 message is sent acknowledgement reset message expires and restart T22 PAGE6 Fascicle VI.8 - Rec. Q.764 Timers used in Recommendation Q.764 (Sheet 5 of 6) Symbol Time-out Cause for Normal At the first At the following value Significanc initiation termination expiry expiry e T23 1 min Local When initial At the receipt of Alert The reception of circuit group the maintenance message should be reset message is acknowledgement personnel and continued until sent restart Timer maintenance T23. Retransmit intervention circuit group occurs reset message. Stop timer T22 T24 < 2 s Local When check tone At the receipt of Report failure - is sent backward check tone T25 1-10 s Local When continuity - Send CCR - check failure is message detected (on receipt of continuity recheck request) T26 1-3 min Local When second Fascicle VI.8 - Rec. Q.764 PAGE1 continuity check - Send CCR - failure is message detected T27 4 min Local When continuity At receipt of Return to idle - recheck request continuity check is requested request message T28 10 s Local When send CQM At receipt of CQR Alert - maintenance PAGE6 Fascicle VI.8 - Rec. Q.764 Timers used in Recommendation Q.764 (Sheet 6 of 6) Symbol Time-out Cause for Normal At the first At the following value Significanc initiation termination expiry expiry e T29 300-600 ms Local First - - - congestion/first congestion indication after T30 expires T30 5-10 s Local First - - - congestion indication T31 > 6 min Local Release of ISDN On expiry - Call reference User part reusable signalling connection based on CO SCCP T32 3-5 s Local On receipt of Fascicle VI.8 - Rec. Q.764 PAGE1 end-to-end On expiry - End-to-end message message to be sent T33 12-15 s Local When send INR On receipt of INF Release call - T34 12-15 s Local When send On receipt of Maintenance - circuits group circuits group action query query response PAGE6 Fascicle VI.8 - Rec. Q.764