rcaman wrote: Thank you for the reply. I do understand the situation. There are telephony conventions that equipment manufacturers have been conforming to for years. When it comes to configuring an ISDN PRI, the usual conditions are programmed, ESF, B8ZS and NI2. The PBX manufacturers require the individual channels to have conventional signalling. This is, typically, E&M. |
The choices are either ISDN PRI or E&M. You can't configure both on the same trunk.
ISDN PRI is out-of-band signaling. The call setup, supervision, teardown, DNIS, etc for all user (bearer) channels is done with one dedicated driver channel.
E&M is in-band signaling. The call setup, supervision, teardown, DNIS, etc for each user channel is done within that individual channel.
The two technologies are not compatible with each other. You can have ISDN PRI where you set clocking, switch type, user/network, and number of digits on both sides of the link. You can have E&M where you set clocking signaling (wink, immediate, delay), and number of digits on both sides of the link.
There is no such thing as "ISDN PRI E&M signaling" There is ISDN PRI and there is E&M. The TA900 supports both, but not both on the same trunk because this is not a thing. Your PBX won't support it either. You have to choose one or the other. Unless giving up one out of 24 talk paths for signaling is a major concern, I would choose the ISDN PRI if your PBX supports it, which Mitel has since the original SX200D with the appropriate card. Call setup is faster and caller-ID with CNAM is supported.
