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From: hundt@wind.bellcore.com (tom hundt)
Newsgroups: comp.sys.ibm.pc
Subject: Dataphone 212A modem (response)
Message-ID: <1800@bellcore.bellcore.com>
Date: Tue, 4-Aug-87 11:34:31 EDT
Article-I.D.: bellcore.1800
Posted: Tue Aug  4 11:34:31 1987
Date-Received: Thu, 6-Aug-87 01:40:25 EDT
Sender: news@bellcore.bellcore.com
Reply-To: hundt@wind.UUCP (tom hundt)
Distribution: world
Lines: 53

The Dataphone 212A is perhaps the first 1200 baud modem; it was certainly
the most popular (by default?) until a few years ago (when Hayes came
along).

It was designed to hook into a business (ie. 1A2, big 50-pin Amphenol
connectors) phone system, and you had to use it with a 1A2 style phone
(the ones with the red hold button and 5 lines along the bottom).

The way you use it is dial a number (manually; this thing does *not*
have autodial capability), and when you hear the carrier press the Hold
button on your phone.  This would disconnect you from hearing the tones, and
indicate to the modem that it should take over.

The buttons on front are as follows:

AL (Analog Loopback)  Used for testing; should echo back to terminal.
ST (Self Test)  Used for testing; should produce some activity and
then normal status lights.
RDL (Remote Data Loopback)  Used for testing in conjunction with another
remotely located (ie. AT&T service) 212A.
DL (Data Loopback)  Also for testing;  I forgot what this does.
HS (High Speed)  Tells it to use 1200 baud.

Indicators are:
TR (Transmit data)
MR (Modem Ready)
HS (High Speed)
RD (Receive Data)

There are jumpers inside to set the options; they should be listed on
case bottom.  It answers (I think) on either 2 or 3 rings (jumper
selects), and will auto-select 1200/300 baud.  (It indicates which back
to the computer on one of the DB-25 lines, so it can set its UART.)

The front cover comes off; press upward on the bottom and the plastic
should come out (forward) when you pull.  Then hinge it upward and the 
top will release also.  The card inside may be pulled out by yanking
on the little metal loop (swivels). 

There are two connectors on back; one is for RS-232 and the other for
the phone line (special cable).


COMMENT
You should probably buy yourself a Hayes equivalent at the next
computer show.  They're only $80, and work better than the 212A
which while it was great in it's day, is no longer.
I don't have the exact connector specs nor the manual since I sold
mine a while back.

 /-^-\  Thomas M. Hundt / BELLCORE Morristown NJ / hundt@bellcore.bellcore.com
 |   |  {seismo|ihnp4|ucbvzx|decvax|ulysses|allegra|clyde}!bellcore!hundt
/--_--\