Spectrum +2 Test Program
Amstrad, 1987

Eprom card for system bus
PCB marked "EPOTEC 1"

This is a test extension for the ZX Spectrum +2, 
similar to the Sinclair test cartridge for the ZX Spectrum 48K.

It can also test the RS232 ports, but you need to plug in a loop back device.

Photo courtesy of Michael Casselden, UK