Here is some info from the X3 Advanced Guide:
MIDI Ch (POD X3 Live & POD X3 Pro only) – choose from MIDI Channel 1-16, or select Omni to have POD X3 Live & Pro respond to all MIDI channels, while transmitting on Channel 1. The MIDI channel chosen from the display user interface will be used as the Channel for Tone 1. Tone 2 will use the next MIDI Channel.
When program change messages 0-127 are received, POD X3 Live & Pro will recall User Presets 01A-32D, and will transmit those same program changes as presets are selected from the POD X3 Live & Pro hardware. It also echoes all program change messages it receives, so it can be connected “thru” to another MIDI device.
Life is what happens to you while you're busy making other plans.
.... John Lennon