OT: Hylafax & digital DID

[Bill Akers]

Joe Chasan wrote:
> On Mon, Aug 09, 2004 at 04:55:01PM -0400, Jay R. Ashworth wrote:
> 
>>On Mon, Aug 09, 2004 at 04:50:54PM -0400, Joe Chasan wrote:
>>
>>>DID is not 2-wire analog - it is a dedicated rj-12 connector which i
>>>believe is different from the regular 2-wire analog - i want the modem
>>>to perform the DID functions, not the phone switch.
>>
>>DID is delivered one of two ways: on a specialized analog trunk,
>>suitable to be terminated by, e.g., a Dialogic DID-120 card (this is
>>fairly rare these days, and only seen on *old* legacy installs) or on a
>>D-4/ESF T-span (or an ISDN PRI).
>>
>>The signalling is commonly DTMF on the analog or T-1 trunks, between
>>the offer wink and the accept wink, and in a digital packet on the PRI.
>>
>>I believe you said yours were digital, but it's not sounding like that
>>now...
> 
> 
> no, its the mismatch between the analog DID device and the digital 
> signal process coming in from the T-1.
> 
> the fax device is a multitech DID modem - they work with only a
> "analog DID trunk line which supports the inbound fax calls and a 
> regular loop-start line for standard inbound/outbound fax transmission."
> 
> however, apparently this is not what DID through T-1 is, which is why
> i'm either looking for some sort of converter that is specific to and
> retains the DID info, or a different modem (and perhaps hylafax, as
> vsi does not support too many).
>
Actually, there are two(at least) ways that a T-1 can be interfaced to 
your telephone system. It had slipped my mind that we actually 
originally had a system that had the digital to analog conversion done 
and then interfaced into our old analog telephone system. If you have 
this condition, then you already have analog signals, but may have 
strange wiring to the internal telephone lines, such as 4-wire or more 
control-signal/voice combinations, which may still require some kind of 
extra interface to a modem. That was the case on our old 1990 or so 
Toshiba system that required an additional 4-port conversion card in the 
system in order to get the proper analog output to the modem.
However, if you have a digital interface directly into your local 
internal telephone system, then you will most likely have two wire(1 
pair)digital lines to the desk sets, in which case my scenario works 
excellently. If your system has some other way of accomplishing this, 
then ignore my comments.

-- 
William Akers
MGM Industries, Inc.
Hendersonville TN USA