[help]simple question about ISDN card


#1

I have used soft phones to test the functionalities of asterisk, now I want to test the isdn phones, but I m not sure, if a normal one port ISDN card good enough to finish the test
some one can tell me?


#2

Bad news. The answer is NO.
You want to emulate the Network side of an ISDN connection.

At the layer 1 (Physic) This requires to run your card in CO mode (emulating the NT1 S/T interface). The framing is not symetric (bit echo needs management) and potentialy provide the phantom power (40V) on the S bus to remote power your phones.

At the layer 2 you need to run the Q.921 (LAPD) master side (in charge of TEI allocation).

At layer 3 (Q.931 / EDDS-1 or NI-1 depending where you live) you need to run the CO side. As the layer 3 protocol is almost symetrical (still you need to send your Setup message in broadcast), that’s might be the easiest assuming you can crack the two previous layers.

Check at junghanns.net/en/quadBRI_produkt.html
This is the type of product that you need

I would expect that most standard cards cannot do that job.

You need to find a card really designed to connect ISDN phone.

If you find one working, list it here.