Question about modems

Frank McConnell fmc at
Wed Nov 13 13:39:40 CST 2019

On Nov 13, 2019, at 10:41, Nigel Johnson 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.

Somebody has to do speed and word format sensing, to pull off something
like the Smartmodem.

Hayes Technical Reference pointed at earlier has a table of supported 
data word formats in section A.1.1, page A-2.

Start bits, data bits, parity, stop bits
1, 7, even/odd, 1 or more
1, 7, none, 2
1, 7, mark/space, 1 or more
1, 8, none, 1 or more

That’s all!

-Frank McConnell

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