It has been reported that the RTWrite function will sometimes not write to the selected port when using Vispro/REXX based programs. This especially is the case when the RTWrite function is the last statement in an event. To fix this problem, simply add any other statement after the RTWrite function call. A simple NOP (no operation) right after the RTWrite call will fix the problem.

This problem does not occur with classical REXX scripts.

I have observed this behaviour in the past but can not duplicate it anymore. I have tested this on a relay card, by actually checking if the correct outputs are turned on and I also have tested it with my FM radio card by changing frequency and volume. It appears to work fine.

I would suspect that the reason could be in how Vispro/REXX poll keyboard and mouse events. If anyone has any suggestions why this happens and how to fix it, please let me know.