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Path: utzoo!linus!decvax!ittvax!dcdwest!sdcsvax!bmcg!cepu!hao!hull
From: hull@hao.UUCP
Newsgroups: net.micro
Subject: Re: anyone know about a single chip 1200 baud modem?
Message-ID: <1056@hao.UUCP>
Date: Tue, 10-Jul-84 16:06:28 EDT
Article-I.D.: hao.1056
Posted: Tue Jul 10 16:06:28 1984
Date-Received: Thu, 12-Jul-84 01:19:48 EDT
References: <1143@druxu.UUCP>
Organization: High Altitude Obs./NCAR, Boulder CO
Lines: 37

Part 2 -the other half (I realize that this does not constitute a SINGLE CHIP
modem, but it's close) the demodulator is the Motorola MC6173, another 24 pin
0.6 inch wide DIP.  The pair together now have similar part numbers, so:
MC6172  Modulator (formerly MC6862).
MC6173  Demodulator.

The MC6173 is a MOS subsystem designed to be integrated into a wide range of
equipment utilizing serial data communication.
The demodulator provides the necssary demodulation and control functions to
implement a serial data communications link over a voice grade channel,
utilizing differential phase shift keying (DPSK) at bit rates of 1200 or
2400 bps.  Phase options are provided for both the U.S. and international
markets.  The MC6173 can be implemented into a wide range of data handling
systems, including stand-alone modems, data storage devices, remote data
communication terminals and I/O interfaces for counters.
N-Channel silicon gate technology permits the MC6173 to operate using a
single voltage supply and be fully TTL compatible.  The demodulator is
compatible with the M6800 microcomputer family, and provides medium-speed
data communications capability.

* Compatible with MC6172 Modulator
* 511-Bit CCITT V.52 Test Pattern
* Terminal interfaces are TTL Compatible
* Compatible functions for 201B/C and V.26 Data Sets
* CCITT and U.S. Phase Options
* 1200/2400 bps Operation

Ok.  TTL compatibility is not RS232 compatibility, so in addition to the
active filters I mentioned in the last submission, you'll have to throw in
some RS232 14-pin line-driver receiver IC's (MC1488,MC1489).  (If you want
RS422 you'll need 9836 9837 8-pin IC's.)  But the real baddie is that 201B/C
(Half-Duplex) is not 212A (Full Duplex), so END GAME.  Next, a look through
the IC MASTER for modem chips.  [I expect a "net attack" from the tech types
on the content of this last paragraph.]
						Howard Hull
{ucbvax!hplabs | allegra!nbires | decvax!stcvax | harpo!seismo | ihnp4!stcvax}
       		        !hao!hull