Port activity viewer?

[Fastest1]

I have been using an RS232 port tester to figure out how to feed my cnc mill. So far I can upload and download but they require different wiring for each process. Not a huge problem but I am pretty sure that was not the intention of the manufacturer. Anyway I am very suspicious of them using a loopback or a jumper across 2 pins that are not normally tied together. So far I have read of no one that has fed this machine via DNC. I have heard that people have but not read. I am sure it can be done and right before the last one is converted over to Keling/HobbyCnc/Gecko I am going to interface with it. Anyway the tester is too slow and or the leds dont really give an indication of what is happening. Is there something less expensive than an oscilloscope, maybe even a downloadable port analyzer that doesnt interfere?

[doorknob]

I'm not certain what you're looking for - would an RS-232 analyzer software package "inline" with your application do the trick? You can capture traces of the two-way communication through the PC's serial port for later analysis in detail.

If so, perhaps the RealTerm serial terminal software will do the trick - the software is free, but a donation is required to get the driver that runs it in "spy mode".

See http://realterm.sourceforge.net/