[VoIP] DP-compatible ATAs

[Shane Young]

Quoting Chad Perkins <chad at maine.maine.edu>:

>> Ah!  Apparently you are confusing DID #s and DID trunks.
>>  I have 100 DID # terminating on a trunk group consisting of 1 trunk.
>> If I had 100 DID trunks it certainly would be cheaper to have 4 or 5
>> T1 spans.  I could not possibly afford that.  It would be pointless
>> for these hobby purposes.
>
> Oh that's a horse of a different color!
>
> I have never heard of NYNEX/Bell Atl/Verzion doing that before;   
> except as Distinctive
> Ringing on analog lines!  This brings me back to a question above;   
> what type of line
> is this?  Can/will they do this on 1B?  I can see how this could be   
> done on a old
> fashion E&M type trunk, but I haven't seen one of those (except in books).

Two-wire analog DID circuit.

I used to have one at home which terminated to a DID card in a Cisco  
voice gateway which signalled SIP to my Asterisk.

I had asked Qwest for 100 consecutive numbers.  They technically gave  
me what I wanted: 7220-7319.  I wasn't clear enough, so I called them  
back and asked if they had 7320-7399 available and they did.  I think  
they charge between $5 and $6 for each block of 20 numbers.

The analog DID circuit is a two wire circuit.  The customer (Me or  
Steph) provides battery.  The CO goes off-hook (potentially waits for  
a wink) and out-pulses some portion of the dialed number.

When there is an answer, the customer reverses polarity to signal to  
the CO there is answer supevision.