• Please review our updated Terms and Rules here

Can’t get serial port working on Z88

O

oktology

Experienced Member
Joined
Mar 24, 2023
Messages
151
Location
Houston TX
Mods, does this belong here or in Portables/Handhelds?

I wired up a cable to adapt the Z88’s non-standard DE9 pinout to standard 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?
 
It's Sinclair so it qualifies for this section.

I can only suggest you check the wiring of your cable against this information:-

Z88 Serial Cable - Z88 Leaflets, Applications & Projects - Cambridge Z88

cambridgez88.jira.com cambridgez88.jira.com

I realise you already know that the Z88 doesn't follow the conventional wiring of a 9-way RS232 port, but thought you might like a reference to check your custom cable against.

Sometimes with RS232 ports (on DOS PCs for example) hardware handshaking is 'on' by default so the port won't TX unless the handshaking lines are in a valid state, and this is often solved for PC RS232 connections by connecting certain of the handshaking signals together in the plug at the PC end. I'm wondering if the Z88 has a similar requirement.
 
SiriusHardware said:
Sometimes with RS232 ports (on DOS PCs for example) hardware handshaking is 'on' by default so the port won't TX unless the handshaking lines are in a valid state,
Click to expand...
This may be the culprit. The Z88 asserts DTR the whole time it's powered on, which my serial adapter or terminal program may balk at.
That at least gives me somewhere to start looking, thanks.
 
Welp, I figured it out: I just know how to wire an RS232 cable correctly, and hadn't crossed RTS/CTS or DTR/DSR lines.
For the Z88, you also need to tie DCD and DSR together on the RS232 side.
 
Thanks for reporting back, it may save anyone else who's trying to do the same thing a little bit of time in future.
 
oktology said:
Welp, I figured it out: I just know how to wire an RS232 cable correctly, and hadn't crossed RTS/CTS or DTR/DSR lines.
For the Z88, you also need to tie DCD and DSR together on the RS232 side.
Click to expand...
Did you know the Tandy Portable Disk Drive BACKPACK can be used with the Z88? Cool!
 
oktology said:
I have one for my M100. What software do I need on the Z88 side?
Click to expand...
set mode Z88. I believe it is in the BPD+ Manual. But you need the right adapter. That is in there too or you can order one from Hey Birt! To me, the Z88 is better than the Model 100 because you can toggle from the Terminal program access to the BPD and the other apps. I don't know if it is true multitasking but it seems like it. We even found a DOS that works. Works great with OZ 4.7.1. That is in the manual and GitHub too. Check the Z88 Facebook page, I did a long post.
 
You must log in or register to reply here.
Back
Top