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From: alewis@gmuvax2.gmu.edu (alewis)
Newsgroups: comp.sys.tandy,sci.electronics
Subject: Re: Modem to Modem minus telephone network
Message-ID: <3632@gmuvax2.gmu.edu>
Date: 26 Feb 91 17:57:44 GMT
References: <1991Feb26.094452@snoc01.enet.dec.com>
Reply-To: alewis@gmuvax2.UUCP (  )
Followup-To: comp.sys.tandy
Organization: George Mason Univ. Fairfax, Va.
Lines: 33

In article <1991Feb26.094452@snoc01.enet.dec.com> cameronjames@snoc01.enet.dec.com (James Cameron) writes:
>For a charity canoe race checkpoint, I want to connect two Tandy 102 laptops
>over a distance of around 500 metres, with the least wiring possible.  The
>machines have integral direct-connect Bell type modems as well as an RS-232
>connector.  [fyi; the Bell modems are otherwise useless in Australia]
>
>My options appear to be
>
>	1)  RS-232 cabling (two core plus shield earth),
>	2)  Standard telephone cabling (two core, twisted pair),
>	3)  Field telephone cabling (one core, with earth return),
>	4)  Radio-modems.
>
[discussion of 1 & 4 omitted]
>
>I guess for these I'd use a telephone power supply, but I don't know how to
>build one nor how it is connected.  Can anyone help me with this?  How would I
>achieve single core operation?

Just hook the two modems together with standard phone cord.  No power
supply should be necessary unless your modems derive their operating
power from the phone company.  If they use the Hayes command set, here's
how to make them talk to one another.  Give one modem the command "ATD".
The "AT" stands for attention, the "D" means dial.  This will cause the
modem to send a carrier as if the phone has already been dialed and
answered.  On the other modem, type "ATA".  That means attention,
answer.  Then you should be all set.  Note that after the dial that
modem will expect a connection within a certain period of time or it
will timeout.  There might be a way to defeat this, or else you'll just
have to coordinate at both ends.


Alan  (:^|


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