Although the Z80-DART (and Z80-SIO) support two channels, most or all existing CPC interfaces seem to use only one channel.
== CP/M ==
The I/O ports are directly supported under CP/M (without needing additional drivers). Like many CP/M functions, the functions are located in the AMSDOS ROM (not on the CP/M disc). These functions are using hardcoded RAM addresses, which conflict with the BASIC memory map, so they can be used only under CP/M, not under BASIC.
== Alternative software ==