User`s guide

Dialogic
®
System Release 6.0 PCI for Windows
®
Release Update, Rev 62 — January 30, 2008 224
Dialogic Corporation
For compatibility with these NTT switches, the new channel block timer can be used in
order to avoid sending the first response to the B channel that was just released by the
previous call. The channel block time is the amount of time to hold off the first response
message from being sent out too quickly to the network on a recently released channel.
The amount of channel block time that the switches typically need is in the range of 0.7-
1.0 second. This helps to prevent the call rejection described above.
T1 Trunk
SetUp (CRN=104) Preferred/Channel Number=12
Alerting (CRN=104)
Disconnect (CRN=104) Channel Number=12
Release (CRN=104) Channel Number=12
Call Proc. (CRN=104) Exclusive/Channel Number=12
Connected State
Release Complete (CRN=104) Channel Number=12
SetUp (CRN=117) Preferred/Channel Number=13
Exclusive/Channel Number=12 (Same
Call Proc. (CRN=117) Channel That Was Just Released)
Alerting (CRN=117)
Cause 44: Requested
Release Complete (CRN=117) Circuit/Channel Not Available
Status (CRN=117)
Release (CRN=117)
NTT ISDN
Network
4:11:23:496
4:11:23:527
31 ms - not enough time,
so switch rejects the call
with ISDN cause 44
Problematical Sequence