I can't seem to find this problem anywhere so I'm hoping somebody here can help me! Up until yesterday, my com port on my Panasonic Toughbook CF-52 was working hunky dory nice. A coworker was using it to troubleshoot and then it happened....the terminal emulation screen went blank and you could no longer type anything to the terminal emulation program. I uninistalled the terminal emulation program, reinstalled it - no good. I was able to narrow down that it is not the terminal emulation program (I tried 3 of them with the same results - hyperterm, Procomm and cryptoterm) but the fact that I when I type, no letters appear on the emulation screen. I uninstalled the com port (I'm on com port 1), rebooted the laptop and the com port was reinstalled but the same issue appears over and over and over - I cannot type to any device using com 1. I tried changing the keyboard types on the emulation programs to no avail. I know the com port works because I can see the OS of my cisco 3750 switch loading just fine but when it comes time for me to start configuring - nada, nothing comes on the screen.
Has anyone ever had anything like this happen to them? I would soooo greatly appreciate any assistance and help anyone can provide.

Thanks very much!

we understand you are using the COM port on laptop to communicate with another device using hyper terminal or some other type of terminal in a simulation program. then suddenly it stopped working.
Of the many things you have tried, you did not say if you had just tried using a simple hardware look BACK tester. This is usually the first thing we use when we suspect a com port has gone bad. We just plug in the little gadget and see if we can talk ourselves. That is to say, on a terminal program you will type a character and that will come back and echo the character so every time you type something it chose back ike this:
hello world
OR
hheellllooo wwoorrlldd
if using half duplex.
One of your junior technicians should have this in his test kit. If you cannot get a terminal program to work with a loop back faster, the com port is shot.

But it it does work on the loop ABACK test, you have bad cable(s).

Ah! I didn't even think about a loopback tester. I've NEVER USED one with a com port so I'm not sure how they're MADE up - can you help me with that? I've got my phone guys that can make it if I know the pin outs.

Thank you sooo very much!!!Goggle com port loopback

http://zone.ni.com/devzone/cda/tut/p/id/3450

http://www.passmark.com/support/loopback.htm
thank you sooo very much for all of your help on this!!!! I'll let you know what happens!