Path: utzoo!utgpu!watmath!egvideo!timk
From: timk@egvideo.UUCP (Tim Kuehn)
Newsgroups: sci.electronics
Subject: Telephone Interfacing (was DTMF --> RS-232 Conversion)
Summary: Need some other telephonyish information
Keywords: DTMF, RS-232, Touch-Tone, on-hook, off-hook
Message-ID: <1905@egvideo.UUCP>
Date: 28 Jan 89 05:00:00 GMT
References: <1441@thumper.bellcore.com> <7139@pyr.gatech.EDU> <2178@van-bc.UUCP>
Reply-To: timk@egvideo.UUCP (Tim Kuehn)
Organization: A Box in the Basement, Kitchener, ON
Lines: 37
Followup-To:sci.electronics

In article <2178@van-bc.UUCP> sl@van-bc.UUCP (pri=-10 Stuart Lynne) writes:
>In article <7139@pyr.gatech.EDU> byron@pyr.UUCP (Byron A Jeff) writes:
>>-attempting to build a DTMF (Touch-Tone) --> RS-232 converter.  I've seen the
>
>>I helped build a DTMF decoder for a school project last quarter. I also
>>-SSI-204 IC's.  Who makes these (Samsung?), and what is the difference between
>
>For example the device should go offhook when "DTR" is raised. A dial tone is 
>produced when RTS goes high and DTMF recogition starts.

What is the definition of an "on-hook" and "off-hook" line? I'm looking for
some information on this and other issues about hooking up to Ma Bell and this
would be quite helpful.


>	[some stuff on what would be nice to do with this equipment]

>Stuart.Lynne@wimsey.bc.ca {ubc-cs,uunet}!van-bc!sl  Vancouver,BC,604-937-7532

I'm working on a project much similar to that for fax machines to mointor
and control useage to/from a customer site. This question about DTMF-RS232 
has been quite informative for part of my project, but I still need to figure
out a way to detect on-hook and off-hook conditions. Also some way of dealing
with the 'ring' signal too. Can someone out there supply me with information 
on how this is done? Or point me towards a publication that has the specs
for the telephone lines and what requirements there are for hooking 3rd party
equipment up to it? 

Many thanks for any and all help!


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