Is the IrDA compatible between the 3c/Siena and 5?
No, as standard the Psions (as strange as it may sound) can’t speak to each other that way. This appears to be due to a problem with the IrDA implementation in the older machines. However, Jim Pollock has developed irSend5, a shareware program that allows the 3c/Siena to send text and OPL files to the Series 5. Word and Data files can be exported as text, transferred to the Series 5 and re-imported into the relevant applications.