cem@intelca.UUCP (Chuck McManis) (11/14/84)
I recently saw the data sheet to a hybrid chip that was a single package
1200 baud modem. Specs from memory were :
Bell 212/103 protocols
On chip DTMF (touch-tone) decoder
On chip DTMF encoder (dialer)
On chip DAA (Data Access Arrangement)
On chip audio amplifier for external speaker
Optional On chip voice synthesizer.
Note that on chip means in the package. There are three or four surface
mounted chips in the package which is slightly larger than the standard
40 pin DIP.
External computer connection looks like an 8251 serial chip.
Other connections are Tip, Ring for the phone line (direct isolation
and other FCC stuff are on the chip)
Audio out/return for the speaker
Vss,Vcc,Vdd + 5 / - 5 and ground
All digital outputs are TTL levels
Icc is 250 mils Iss < 50 mils.
This really looks like a wire it up and use it type modem. The person
with the data sheet said he could get me oneies for $300 and
$350 for the design kit. (Probably consists of a PC board + box.)
The company is called Xecom and they are in Milpitas California. If
they can get their production costs down (surface mounting things
really is tough to automate) and this chip gets into the <$150
range, a really nice modem could be built for very little additional
investment. It seems targeted for the people who want to put a smart
modem on their mother board, but could easily be connected to a
micro controller and used as a more traditional modem. I think it
could really fly.
--
-- Chuck - - - D I S C L A I M E R - - -
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