Thanks John,
Do you still have that old Pronto?
Some of the experiments that may be needed to solve this would be easier with an old (pre NG) Pronto. Other experiments need a second PC readable IR learning device (such as a second Pronto) in addition to the Pronto being tested.
I'm afraid I don't have an old (non NG) pronto, but I do have two NG colour Prontos.
If I understand you correctly, a short press always learns something but the learned command never works.
Yes, that's correct.
I see your ideas about capturing the end of the codes. I will try this and revert back. Unfortunately I'm still at work at it's 7.30pm so I don't think I'll have time for this tonight. I'll try tomorrow.
Regards
Lee