Connecting A Z88 To An Electron

By Alan Richardson

Originally published in EUG #54

The Z88 is a Z80-based 8-bit machine that uses a version of BBC BASIC.

Perhaps there is room for including the Z88 in the 8-bit family covered by EUG. I believe it was Sir Clive Sinclair's last computer effort.

The Z88 becomes a more useful machine when its files can be saved to disk via an Electron (or other machine). The benefits are twofold: the disk save is more reliable (also freeing space in the Z88), and it reduces the risk of loss when changing batteries.

I have had a Cambridge Z88 for a while but because my Electron has served me so well, and I am more familiar with it, I have not put as much effort into understanding the Z88 as I might have. One reason for being disillusioned was having lost data in it more than once. Now, with disk saving a reality, I am more interested in using it in that it becomes a more reliable tool. (Hopelessly out of date, some will say, it can't access the Internet!)

PC Link II works well but for some reason is slow. I haven't found out why this is.

Our local Acorn User Group noted in a recent newsletter that there was a web site operated by John Allen that specifically mentioned the Z88.

I asked a friend to download what was available for the Z88 and it included a program called Archive which runs on the Electron and, when connected to the Z88 by an RS423/RS232C connecting lead, will work with the Z88's Import Export feature. This allows files to be saved to disk as one large archive file which can then be loaded back in its entirety or file by file. A nice feature, and it's fairly quick compared with PC Link.

Archive works well when connected to a Electron or a BBC except for a problem with option 3 on the menu. When using option 3, the program checks for two characters at the beginning of the archived file. These two characters are &1B and &4E. If there are not found in order it gives a "File type mismatch" error. Unfortunately, the Z88 uses an X-on, X-off protocol that is not quite standard. It uses &11. &11 is hence found at the beginning of the archived file in addition to the required characters and Archive, as it was, did not check the incoming characters. As a result, nine times out of ten, one could not selectively restore files even though the whole file could be restored without problems.

Once the problem was identified it was a matter of finding the solution. My friend who did the downloading also has a Z88. He was able to provide a few additional lines of machine code that ensured the archived file started with &1B. It now works well.

I had e-mailed John Allen who wrote the program, and who still has a Z88 web site that appears to be operational. However, he replied that the programs were written a long time ago and didn't give me any additional magazine references. I had requested them because none of the references I could find related to the second part of the Archive program.

He also wrote an excellent book for the Z88 - Z88 Pipedream: A Dabhand Guide. His web site is

If anyone in the group is using a Z88 I'd like to compare notes. My email is

I'd be happy to pass on the "fix" for Archive.

Alan Richardson, EUG #54