Can’t get serial port to work

Discussion forums for users of the Cambridge Z88 Portable Computer
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okto
Posts: 28
Joined: Sat Apr 22, 2023 7:48 am

Can’t get serial port to work

Post by okto »

I wired up an adapter cable for RS232 and I can’t get it to pass data no matter what I try. I’ve triple-checked the pinout, I’ve tried it with every combination of cables I have, both null-modem and straight through, and I cannot get it to talk to my Mac. Tested it with both my Z88s, no dice on either one.

I’m using a Keyspan USB serial adapter that works fine with all my other old computers. Same adapter, same software, settings match on the terminal app and the Z88.

I’m at a loss. What am I doing wrong?
Chris_68
Posts: 16
Joined: Fri Jan 20, 2023 8:05 am

Re: Can’t get serial port to work

Post by Chris_68 »

Hi,

Did you connect following the instruction here:
https://cambridgez88.jira.com/wiki/spac ... rial+Cable
?
Are you sure the serial port on z88 is working correctly?
/C
Jbizzel
Posts: 65
Joined: Thu Apr 23, 2020 6:58 pm

Re: Can’t get serial port to work

Post by Jbizzel »

This is the adapter you need. I have a spare if needed.

Code: Select all

z88	pc

	1--+
2-------2  |
3-------3  |
4-------8  |
5-------7  |
	   |  
7-------5  |
8--+	   |
   |       |
9--+----6--+
okto
Posts: 28
Joined: Sat Apr 22, 2023 7:48 am

Re: Can’t get serial port to work

Post by okto »

Turns out I just don’t understand how RS232 works and I didn’t cross DTR/DSR or RTS/CTS. Got it working now.

Thanks for the links, y’all.
Chris_68
Posts: 16
Joined: Fri Jan 20, 2023 8:05 am

Re: Can’t get serial port to work

Post by Chris_68 »

Hi,

Great, glad you sorted it.
okto
Posts: 28
Joined: Sat Apr 22, 2023 7:48 am

Re: Can’t get serial port to work

Post by okto »

Jbizzel wrote: Fri May 12, 2023 1:57 am This is the adapter you need. I have a spare if needed.
My cable doesn't have Z88 pin 8 or 9 tied together, but seems to work fine.
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