What's the difference between a channel, channel pair, and channel group?

For most TraXX commands, you have to specify either a channel, channel pair, or channel group.

A channel is a single mono channel of audio.
A channel pair is a stereo pair containing two channels.
A channel group is a user-defined group of channels.

Channels are referred to as C1-C16. Channel Pairs are P1-P8. Channel Groups are G1-G13.

For example, a play command to play "file.mp3" to Channel Pair 3 would look like: "file.mp3"P3PL

Being an 8-stereo channel player, the 8TraXX with Ethernet can only operate with Channel Pairs and Channel Groups. ProTraXX and TourTraXX, being 16 channel players, are also capable of operating on individual mono Channels.