Question about modems

Nigel Johnson nw.johnson at
Wed Nov 13 15:41:41 CST 2019

No. While each end might be able to communicate with the local modem in 
command mode using different parameters, when they are in connected mode 
the modems will not convert anything, just pass the exact format along. 
So if one end is expecting 7E2 and the other is sending 8N1 there will 
be a 50% chance that parity errors will be received.



On 13/11/2019 16:16, Grant Taylor via cctalk wrote:
> On 11/13/19 1:31 PM, Fred Cisin via cctalk wrote:
>> But, stuff like commands to the modem didn't need much of that, and 
>> needed to be able to communicate in spite of wrong parameters.  It 
>> made sense for a modem to recognize a command, even with wrong 
>> parity, etc.
> Okay....
> Now I'm thinking that there are really two phases / modes of 
> communications:  1) computer to modem commands, and 2) computer to 
> computer via modem connection data.
> I think my previous statement applies to #2.  I can see the value in 
> #1 being more liberal in what it recognizes and accepts.
> But, I'd still be surprised if the following would work for #2.
> [A]---(7E2)---{modem}==={modem}---(8N1)---[B]
> Would A and B be able to transfer data between each other with 
> different (local) settings?

Nigel Johnson

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