Question about modems

Chuck Guzis cclist at
Wed Nov 13 13:10:15 CST 2019

On 11/13/19 10:41 AM, Nigel Johnson via cctalk wrote:
> On 13/11/2019 13:36, Chuck Guzis via cctalk wrote:
>> There are other "oddball" combinations, such as 8E1 and 8O1, which sends
>> a 9-bit data frame.  You can see datasheets on some UARTs as well as MCU
>> UARTs that support the 9 bit packet.
> According to the diagram of the Smartmodem there is no UART, the 1488s
> and 1489s go directly to the Z80.
>> Also, don't/doesn't TDD (5 level code) use 5E2 or some such.  Same for
>> Telex/TWX.
> Not sure 5 level code (ITU #2) ever had parity, but to confuse the issue
> even further, there was a 1.5 stop bit option too, for mechanical machines!

Strange that--not even a DART?  Well, I was always a Racal Vadic guy
back in the day of 300 bps.

Also, 134.5 for selectric machines.


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