17 Jun
2013
17 Jun
'13
6:54 p.m.
Timely discussion - just last week Rob and I here in Vancouver got a
Model 28 teletype working and printing from a computer, in
preparation for a film production request.
The 28 teletype we are using has gears for 75 baud, so that's what we
needed to send (with 5 data bits and 1.5 (minimum) stop bits).
Rob brought along 3 serial converters, 2 of them wouldn't work for
some reason or other, but one successfully drove the 28. It's a model
GUC232A, and appears to be still available from Iogear.
I just did some further tests of the serial converter, observed on a
scope with the following outcome:
Requested Result
BPS
--------- ------
300 - good
150 - good
134 - produces 9600
110 - produces 9600
75 - good
50 - invalid-value error at runtime
Environment: python test program, MacOSX/10.4, G5 processor
So it can successully drive an older Model 28 down at 75-bps/5-bit,
but isn't going to work for the more-modern KSR-33 (110-bps/8-bit),
at least not from this environment. Could check it on Windows as it
might be a driver/parameters issue. One wonders whether the driver
programmer just didn't bother to calculate the divisors for the
oddball rates.
And there a KSR-33 here I wanted to use it on...