[VoIP] DPO trunks

[John R. Covert]

Among the mods that our intrepid Zaptel/Zapata hackers have done
here, is there anyone who has modified the code to allow a Digium
TDM4xxP FXS module to support DPO, in particular, the required
polarity reversal when supervision occurs?

If so, I would like to get it into the official code base.
I've got an Asterisk/Digium potential customer served out of
YLKNNTXNDS0, which will not provide any other kind of DIDs
(and is currently served by this kind of DID).  Well, they
would give them a PRI for $3500, but the company only needs
three DIDs.

I actually think they would be better off using their current
Adtran off a TE110P, but then we have the question of making
the channel card work in DPO mode.  It might be as simple as
telling Asterisk that it's E&M, but telling the channel bank
(as they do today for their SphereCall PBX) that it's DPO.

/john