[Asterisk-Users] DID line with Adtran TA750 and T100p

Kekin Dand kdand at usinteractive.com
Sat Oct 18 13:02:22 MST 2003


Hello,

I new to this, but with the help of mailing lists archives and IRC I am able
to build my PBX. Thanks to all who had help me to reach till here.

I am stuck at a point where I can't find the solution on mailing lists or
even on IRC. 

I have individual 4 DID (Direct Inward Line) coming from Telco and
terminating into TA 750 to FXS card. Many of them told that Phone instrument
terminates to FXS card that is correct. When I check with Adtran Tech they
told it should be terminated into FXS card, with DPO mode on each DID
circuit. 
I checked this on there website also here it is:

How do I extend a DID (Direct Inward Dial) line from the telephone company
using voice FXO and FXS cards? 
This connection seems backwards when compared to the OPX line. Remember with
a DID line, the telco acts like the switch (FXO) and the customer supplies
the battery (FXS). The customer connects the telco DID line to our FXS card
and the DID trunk of the PBX to the FXO card. These voice lines originate
from telco and terminate into the PBX. They will never originate from the
PBX. When a call comes into the telco's switch with your telephone number,
the telco closes a switch connected to your cable pair. This causes loop
current to flow from the FXS card. The FXS card sends signal bits across the
T1 to the FXO card who then closes his switch causing loop current to flow
from the DID interface card on the PBX. The PBX then signals the telco (with
a wink) that it is ready for the call. The PBX does this by reversing the
battery's polarity. When the Telco sees this wink, the Telco then passes the
DNIS digits through the talk path into the PBX. The PBX uses the DNIS digits
to route the call to the appropriate phone. The call can terminate from
either end. If the person at the PBX hangs up the loop current (from the PBX
to the telco) will stop flowing and Telco will return to an idle condition
by opening their switch. The call can also be terminated from the telco side
if the incoming caller hangs up. When this happens, the telco opens their
switch and loop current stops flowing. The PBX then returns to an idle
condition.

My PBX communicates with TA750 on T1 with T100p card.
I don't know what signaling needs to be set in Zaptel.conf and Zapata.conf
files, so that once Telco send the signal it will see the PBX and rings that

DID extensions. 

Has anyone had done this? Please let me know, I have to put this machine
live by Monday and I stuck where I have no clue what to do.

Thanks 
Regards,
KD





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