I'm not sure what others would be interested in the way of features, if such a device was to be created, but I was thinking about the following:
Computer to TTY: USB at standard serial speeds of 2400 to 9600 bps. Ideally with XonXoff flow control and RTS/CTS flow control for the downstream path (however, there are windows driver issues with flow control on USB<->Serial devices).
Downstream and upstream functions are full duplex.
Downstream functions:
- Convert ASCII to 5 unit Baudot/Murray codes: ITA#2, US MIL, others?
- TTY output speeds of 60, 66, 75 and 100 WPM.
- Convert ASCII LF to Baudot CR CR LF, ignore ASCII CR
- Binary Mark/Space output that can open/close HV 60mA loop circuit, polarity independent
- Hi Tone AFSK Mark/Space output (to drive TU in those cases where someone wants to use or demo a TU with their TTY).
Upstream Functions:
-
Binary Mark/Space current sense input of HV 60 mA loop circuit, polarity independent
-
TTY input speeds of 60, 66, 75 and 100 WPM.
- Convert Baudot/Murray codes (ITA#2, US MIL, others?) to ASCI
Also could do a motor control. Start motor when characters are in
downstream queue (with 2 second startup char output delay for the motor
to stabilize) and then motor off when no characters are in downstream
queue for more than 10 seconds (or whatever time is wanted).
Assuming the printer has sensors for paper out and paper jam, it might be possible to include an AnswerBack function, if that might be useful.
Paul, ad7i