On 12/05/2021 18:26, Peter Able wrote:
snip

IIRC the spec for RS232 was +/-3 to +/-15v.Â* How many implementations
obeyed that?Â* Not to mention that random data in two stop bits mode
would not average zero volts !

PA

This was for a specific piece of kit and was adjusted accordingly. If
we'd used two stop bits, the crayon mark on the scale would have been
moved to take account of this.

****.

--
Cheers
Clive