Ven-Tel autodial modem (c. 1982)

From: Will Roberts <>
Date: Mon May 31 12:30:02 2004

I'm still cleaning the attic. I just found a Ven-Tel MD-212plus
modem of vintage 1982 or so.

This modem is unusual because it was one of the first to include
auto-dialing controlled via its RS-232 interface data stream.

Today, there is nothing unusual about embedded commands for dialing,
but at the time, the only modems that could handle dialing were
costly and bulky devices provided by Bell and requiring software
support in the computer. (I believe that D C Hayes had just come
out with a small 300-baud modem for the Apple II which introduced
the AT-command set.)

Racal-Vadic even published a "white paper" with the title:
"Auto-Dialing is not Trivial" about that time. It went into detail
about the various dial-tones, audible ring and busy signals,
intercept recordings and other obstacles which a modem would
encounter on the public switched telephone network.

There is a photo of this VenTel MD-212plus 300/1200 bit/sec modem

It's on its way to that great modem resting place unless someone
wants to give it a home for the cost of postage. It would look
very nice sitting on top of a PDP-8.

With packing material, it weighs slightly less than 6 lbs. including
the power supply (which is hard-wired to the modem.)

Email me if you have any interest. Provide your zip code and
preferred method of shipping (Priority Mail, Parcel Post, UPS) and
I'll calculate the exact rate. First come, first served. Offer
expires 6-15-2004. Void where spouse objects to any more techie junk
in the house. ;)


still cleaning the Old Bear's Attic
Received on Mon May 31 2004 - 12:30:02 BST

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