Is the Lego 8884 IR Receiver compatible with earlier IR Speed Remotes e.g. from set 7897? I'm thinking of buying the new Train power function, e.g. 8884 IR Receiver, 88000 Battery Box, and 8879 IR Speed Remote. However I already have the set 7897, is the Speed Remote from this set compatible with 8884 IR Receiver ? Does anyone know ?
I think the train motor is compatible by the way, correct me if I'm wrong.
I think RC devices are not compatible with PF devices due using different IR protocols.

For instance, see this forum thread for more explanation. Also this cool site.

Summarizing,


RC and PF can use the same rails
RC and PF cannot use the same remote controllers
RC and PF uses different engines:


RC places it in bogie (as 9v do)
PF places it in body