Z88 Serial Cable

https://tinyurl.com/k27fqm3

Introduction

None of the Computer Links will work without a Cable.

At the time that the Z88 was designed, there was no standard connector, so Cambridge Computer made up its own. It uses the 9 way 'D' type connector which are used with the modern computers, but they are different in two different ways.

  • Mechanically - they do not have the stand-offs to accept the screw down connectors. This means that if a normal computer cable is used, it will not fit completely in the Z88 as the screws on the cable connector will prevent it from plugging into the Z88.

Z88 9 way connector

 The Z88 Serial Cable connector do not have any screws fitted, so it fits into the Z88 perfectly. So why not just remove the screws you may ask?

  • Electrically - The bad news that even the connections to the nine pins are different.

There is a lot of misinformation on the net about making your own cables. This is because initially Cambridge used IMP/EXP built in software which used software handshaking and just 3 connections. This was later replaced with PC Link II which used hardware handshaking and used more connections for hardware handshaking. Other companies then also started making computer cables for the Z88 which may have used different wire colours and worked with their software, but may still not work with the current one.

Before using any cable, please check it against the pinouts given here, or just get the correct cable. Then any of the transfer programs may be used with the Z88 confidently.


9 way Cable with screws

Z88 Links to be modified


Z88
Desktop25 Way
PC Cable
25 Way
Serial
Printer Cable
Z88-To-Mac




Computer Cable
at Z88 end








Z88 to Desktop
RS-232 Cable
Z88 Cables for other devices modified to be used with the Desktop using optional USB Serial adapter.
Z88 plug used but the other connector removed & replaced with a 9 way 'D' socket for the Desktop. 

Z88
Desktop USB 
Serial Socket
Desktop Old Standard 
Serial Socket
Printer PlugOld Mac modem
connector

Connector
diagrams
are exterior
views

9 way
'D' plug


Cable

9 way
'D'socket

25 way
'D'socket

25 way 'D'plug

Mini-DIN-8
connector


Signals

Pin-outs



Pin-outs

Colour of cable to be connected to the Desktop

NOTE: Do not rely on these colours. Different manufactures used different colours. 
Check that the connections are electrically correct.

Signals


1

DO NOT USE for for RS232 signals.
It carries 5v at 10uA even when the machine is off. Not Used

TxD22 BlackRed / BlackBrown RxD
RxD33 RedYellowRedTxD
RTS48 BrownPurpleOrangeCTS
DCD8
4 Not UsedDTR
CTS57  YellowWhite / BlackYellowRTS

6
6 Not Used
GND7 / Gnd5 / GndOrange & ShieldBlue / White & ShieldGreenGND
DTR91 / 6All four pins (8 - 9 on Z88 and 1 -6 on other side) connected for Eazylink handshaking.DSR


See Appendix B in the Z88 User Guide for full explanation.

Recently, the older type of Z88 computer cables have appeared on the market. These are:

  • 25 way to Z88 Cable and
  • Z88 to Mac Cable

If you are handy with a soldering iron, or wish to buy an adapter, the following give clear instructions on how to modify these cables and save money from buying the standard cables.

Benny Boogaert shows you how to modify these cables..


Modifying Z88 to Mac Cable to 9 way PC cable.

1. Cut off
the Mac
Plug

2. Strip
1 cm and
tin wires

3.

Brown 2
Red 3
Green 5

4.

Yellow 7
Orange 8


5.

finished
socket 


6.

connector
housing

7.

cables
together

8. comms linux


Modifying Z88 to PC Cable - 25 way to 9 way socket



black2-
red3-
orange5
yellow7-
brown8

red2-
yellow3-
blue5


white7-
purple8

Finally
yellow7-

brown8

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