Thanks for the info. I am somewhat familiar with PSIP in the OTA environment, but I have no knowledge of how PSIP plays in the cable environment.
I would have guessed that the channel mapping from cable would have come from the cable company-inserted data stream (somehow--I don't know how) and would have been specific to their channel assignments from a given head end.
Even without cable company intervention, PSIP data transmitted with a DTV signal essentially tells the receiver which logical channel they have chosen, which typically matches their OTA channel number as a base and then adds a subchannel number with it.
I will have to dig around some more to see if I can't come up with some technical description of how cable company channel mapping works, with or without a cable card or cabel company STB.