[VoIP] Dial Pulse converter specifications

[Steph Kerman]

More loop supervision?  What do you mean?

1)  It needs to connect into the loop.  A design was published that 
installed in a phone and connected directly to the dial pulse contacts.  
This is not a suitable configuration.

2)  It needs to provide a DC current path during the dial pulse break 
intervals to prevent the downstream device from seeing each pulse as a 
disconnect. 

3)  It should support 10 PPS to 20 PPS operation.  20 PPS operation is 
not supported on some modern exchanges that support 10 PPS operation.  
Supporting 20 PPS operation would make it possible to use 20 PPS dials 
both in these environments and in SXS environments equipped with TT 
converters.

4)  It should work with real-world dial pulses that have pulse 
characteristics at the extremes of the readjustment limits published by 
the Bell System.  This includes ratio, average and instantaneous speed 
and contact bounce.

5)  A goal would be to make it loop powered, but that's not an absolute 
necessity.  It could be designed to only consume power during pulse 
conversion, so that battery operation could be achieved with very long 
battery life.

6)  It should use readily available commercial electronic components: no 
antique switching equipment relays with pure unobtainium contacts.

7)  A printed circuit board would be designed and procured from a 
commercial prototype board house to permit easy assembly without random 
hand wiring.

Steph

john jones wrote:
> Since so many VoIP ATA's don't support DP dialing,
> there has been a suggestion to construct a TT to DP
> converter.
>
> I'd like to start collecting specifications of what
> this device needs to do.
>
> I expect that on the FXS side, it ought to perform in
> ways similar to the teltone converters often installed
> between Linefinders and the 1st selector although I
> imagine that more loop supervision is required.
>
> Let's get a dialog going on this.
>
> Thanks!
>
> John
>