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OP-80A

PostPosted: October 7th, 2019, 6:12 am
by Hammond
I recently assembled, from kit form, a reproduction OP-80A punched paper tape reader.
I would like to connect it to my ALTAIR-8800 clone computer. Can anyone tell me if this is possible and, if so, how I should go about it?
Cheers

Re: OP-80A

PostPosted: October 7th, 2019, 8:13 pm
by toml_12953
Hammond wrote:I recently assembled, from kit form, a reproduction OP-80A punched paper tape reader.
I would like to connect it to my ALTAIR-8800 clone computer. Can anyone tell me if this is possible and, if so, how I should go about it?
Cheers


I believe it's a parallel unit. If so, you'll have to find a way to convert the Clone's serial output to the parallel input needed by the tape unit.

If you're a do-it-yourselfer, you could investigate this TI chip

http://www.ti.com/product/SN74LV8153

If not, maybe this could do it for you:

https://www.ebay.com/itm/HP-Serial-to-Parallel-Black-Adapter-NEW-127463-001-Compaq-Printer-101868-B21-/392026772227

Tom L

Re: OP-80A

PostPosted: October 8th, 2019, 10:49 am
by AltairClone
The Altair Clone does not have any parallel ports, so the best bet would be to come in through a serial port (e.g., the cassette interface port at 6/7 would be ideal). As Tom mentioned, the OP-80A uses a parallel interface, so a conversion from parallel TTL levels to serial RS-232 levels is required. In addition, the OP-80A receives power over the parallel interface, so power out to the OP-80A must be included in the interface circuit.

Mike

Re: OP-80A

PostPosted: October 16th, 2019, 12:28 pm
by phoenix
Hammond,

The OPO-80A does not receive serial data, it produces parallel data. Therefore neither of the serial to parallel converters listed in the first reply will work. You need to convert parallel data from the OP-80A to serial data which can be sent to the Clone. I'd recommend the TI 74LS165 (60 cents) to shift the parallel bits from the Op-80A to serial output. Then use the MIKROE MAX232 ($8) to bring the TTL up to RS232 level. Good Luck!

Re: OP-80A

PostPosted: January 30th, 2020, 3:13 pm
by GlassTTY
Not sure if this is of any interest but I used an Arduino Micro with a small sketch to solve the parallel to serial issue with my OP-80a. I am sure there are more elegant hardware solutions, however, my hardware skills are quite weak and I wanted a quick and simple to build solution.

Full details are here... https://glasstty.com/wiki/index.php/The ... Paper_Tape

I hope it helps.