I would classify the following:
Telemetry:anything that is sent down that originates from the satellite
Transponder: anything that relays information from ground
Telecommand: anything used for controlling the satellite.
This last option would not be used a lot, but it should be mentioned.
APRS would be transponder, SSTV would be telemetry, unless its a SSTV relay, in which case it would be transponder.
I think everything should fit into these three categories?
FUNcube technical team member