Using an ASR 33 Teletype with IBM PC

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Using an ASR 33 Teletype with IBM PC	by Bill Degnan - 06/14/2011 20:56
There is a socketed shunt module on the bottom right of the original IBM async board, just pull it out and re-insert upside down (so the dot is pointing down) for current loop. If you're going to use slot 8 of an IBM PC or XT a jumper is required on connector J13. Why I don't know off-hand. Plug a regular-old EIA connector into the serial card in the back. The serial connector pins you need to connect to the teletype are are: pin 9 = + transmit current loop data pin 11 = - transmit current loop data pin 18 = + receive current loop data pin 25 = - receive current loop data [pin 25 is the bottom right (bottom = row of 12 pins)] Then connect to ASR 33: Transmitted data return (-) attaches to terminal strip screw 6 or "number 2 connector" #7 Received data return (-) attaches to terminal strip screw 3 or num 2 connector #5 Transmitted data send (+): Terminal Strip 7, #2 connector 8 received data send (+): Term strip 4, #2 connector #6. If the tty stops chattering you at least have a current loop. You'll need some sort of terminal program just like you'd use with an RS232 terminal connection, but you will need to use 110b, etc. Source - Paraphrase from IBM Technical Reference Manual volume 2 Reply
Using ASR 33 as IBM PC Console	by Bill Degnan - 02/08/2013 09:51
If you have an IBM Asynchronous Communications Adapter configured for current loop, then you can in theory use a teletype as the console to interface with the PC. MODE COM1:110,N,8,1 CTTY COM1 [I need to try this myself, if anyone reads this post and has corrections please advise.] -------- Using the software that came with the IBM Asynchronous Communications adapter it should also be possible to make a direct connection to the teletype via the serial port and use to upload ASCII into a file (while papertape is being read in by the TTY reader) Reply
Cable for IBM PC to Teletype	by Bill Degnan - 02/11/2013 22:09
In addition to connecting pins 9,11,18,25 from the async card to the teletype, Chuck(G) of vintage-computer.com forums says "...the PC still pays attention to DSR, DTR, RTS and CTS. So you still have to jumper 4-5 and 6-8-20 on the PC DB25. .. Request-to-send -> Clear-to-send (pin 4 to pin 5) Data Set Ready -> Carrier detect -> Data terminal ready (pin 6 to 8 to 20)" Thanks Chuck! Reply
IBM Async Card Current Loop Jumper	by Bill Degnan - 02/19/2013 21:02
Photo of the jumper in the "current loop" position. Reply