ZON X FOR SPECTRUM
BI-PAK has now made the ZON X-81 sound box available for the Spectrum as well as the ZX-81. It contains an 8912 three-channel sound chip with a powerful amplifier, loudspeaker and volume control in a 6in. x 3in. x 2in. black box. Everything is powered from the computer and some complicated sounds can be generated which will repeat without the aid of the computer.
As the device is I/O-mapped it requires machine code on the ZX-81 but an ingenious method of making it compatible with other REM-located machine code makes it easy. The Spectrum must use an additional board which contains a 3.5MHz oscillator to stabilise the frequency used. That is about 2in. long and fits between the Spectrum and the ZON 81.
One problem with the decoding makes it incompatible with the Microdrive and RS232 intended for the Spectrum as it uses A4, which Sinclair has already declared will be used by its devices. Apart from that it works well on both machines, providing a cheap and easy alternative to the BEEP command.
Bi-Pack sells the ZON X for £25.95 and the Spectrum board for £6.80. Bi-Pak is at PO Box 6, 63a High Street, Ware, Herts. Tel: 0920 3182.