OK, reading up, it looks like the Blau Thummer RCIII remote is not compatible with the empeg because it does not use the correct frequency.

Should it not then be possible to just swap out the crystal in the thummer so
that it will make the correct frequency? I should think so.

Hmmm... If I connect an IR receiver to a frequency counter, I should be able to see the frequency of IR transmissions, no?