Simulated telephone

Rik Bos hp-fix at
Tue Aug 24 12:44:50 CDT 2010

> -----Oorspronkelijk bericht-----
> Van: cctalk-bounces at 
> [mailto:cctalk-bounces at] Namens Jim Scheef
> Verzonden: dinsdag 24 augustus 2010 17:51
> Aan: General Discussion: On-Topic and Off-Topic Posts
> Onderwerp: Simulated telephone 
> Hello all,
> I would like to play^H^H^H^H use some of my vintage portables 
> the way they were intended. For example, the Radio Shack 
> Model 100 and the HP 110 Portable have 300bps internal 
> modems. I have several other modems thru which these machines 
> could talk to a *NIX but I do not want to pay for multiple 
> phone lines in my home. How can I simulate a POTS connection 
> between these modems? I don't need a dial tone or ringing, 
> etc., as I can just tell one machine to connect and the other 
> to answer. 
> Way back I heard that a few modems would work if the tip and 
> ring wires of the modems were crossed and connected, but most 
> need something more than that. Is there some simple circuit I 
> could build? Surely I'm not the first to want to avoid phone 
> bills for such play^H^H^H^H testing.
> Jim

If you can get your hands on a small old analog house phone unit, then you
can  build your own privat phone network.
I've an old PTT Vox unit(dutch phone company)which understands ATF and pulse
dailing, 4 internal lines enough to play with modems etc..


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