You can test the PSG sound channels by typing simple SOUND commands in BASIC. You should hear a 440Hz sound for 10 seconds at full volume for each of these commands:
SOUND 1,440142,1000,15 should produce sound in the left speaker. (channel A) SOUND 2,440142,1000,15 should produce sound in both speakers. (channel B) SOUND 4,440142,1000,15 should produce sound in the right speaker. (channel C)
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The PSG chip family is composed of 3 variants:
* the AY-3-8910 , with two 8-bit I/O ports and a 40-pin package* the AY-3-8912 , with one 8-bit I/O port and a 28-pin package* the AY-3-8913 , with no I/O port and a 24-pin package
In addition to the CPC, these chips were also used in the [[KC Compact]], [[ZX Spectrum]], [[MSX]], [[Oric-1/Atmos|Oric]], [[EG2000 Colour Genie]], [[Vectrex]], [[Intellivision]] and in the Mockingboard expansion for the [[Apple II]].