ORIGINAL: MikeL
ZPCM and SPCM are just two different types of PCM encoding. ZPCM is the older type, with 512 steps of resolution. SPCM is the newer type, with 1,024 steps of resolution. You set the transmitter to the type of PCM that your PCM receiver is designed for.
That's what you do
IF you have a transmitter with selection capability.