Maplin ZX81 Voice PCB

Discussions about Sinclair ZX80 and ZX81 Hardware
Post Reply
Posts: 7
Joined: Wed Feb 20, 2019 1:33 pm

Maplin ZX81 Voice PCB

Post by hinotor1 »

Hi All,

I have a Maplin ZX81 Voice unit for the I'm keen to test with my ZX81. It looks like I will need to build an expansion I/O board as I can't find any available.
Has anyone else built their own DIY I/O board and has any recommendations or advice?

Many thanks! :)


User avatar
Posts: 2986
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: Maplin ZX81 Voice PCB

Post by 1024MAK »

This photo shows the Maplin expansion bus type card:

These links should help: ... vzx81.html



Posts: 2030
Joined: Wed Jun 18, 2008 2:00 pm

Re: Maplin ZX81 Voice PCB

Post by Moggy »

Another alternative is to solder an edge connector onto the board. Also the link provided by Mark for the Maplin board is really important as this board doesn't use the standard allophone codes(0-63 decimal) for the SPO256 chip (a quick glance shows 192 decimal is added to a standard allophone code for this board), some of the standard codes do work for individual ooo's and aas etc but not all, especially in constructed sentences .

SPO256 data sheet for comparison ... ... 56-AL2.pdf

An item that may be of interest can be found here.... ... sizers.pdf

Post Reply