Troubleshooting com ports

[mhubbard]

I need some help on exactly how you troubleshoot a com port? I have a client who connects a device to his com port 1 on his pc and all of a sudden it has stopped working. The OS is Win ME. I dont have a lot of dealings with com port issues so I am not sure exactly where to start. Can someone point me to a good com port testing program? I think there are some ways within Windows as well to test it. Thanks for the help.

[Matridom]

there are a few utiliies out there to test com ports, but your best bet is to find one that uses loopback adapters, you may have to make them (if you can get a wiring diagram). Loopbacks are the quickest and easiest way to test a com port. your other option is to plug a known working device into it (liek a moue) and see if it works.

[Ya_know]

Is there a conflict in the device manager? If you have IRQ or memory address conflicts apparent, that could be your problem...

[NeuromancerIV]

Hmmm, have you tried the device on another machine or another serial device on their PC?

We use, like Matridom suggested, loopback testers, and typically troubleshooter6.5 to test.

Has the customer installed any additional software that may use that port recently? external modem?/updated modem drivers?/new/reinstalled modem? card scanner? Palm Pilot or other PDA software? Oftimes these will seize a com port. Did they somehow remove the settings or disable it? Also could check the bios and make sure they didn't monkey with any manual com port settings


typical settings are *please someone correct me if i'm wrong*

port i/o range irq
Com1 3f8-3ff 4
Com2 2f8-2ff 3
Com3 3e8-3ef 4
Com4 2e8-2ef 3



Otherwise try going to the control panel in Windows and go to the IRQ listing section and see if there are any device conflicts listed. That'll hopefully get you started.

Good Luck!

[tracker0563]

Best bet is a dos based program that uses hardware loopbacks.

Anyone remember Check-it?

Maybe even stick a serial mouse on it and see what happens?


Craig

[RejectionMan]

i always use a crappy external modem, and try to hyper terminal to it. if it detects the device, and you can send command then its working...

other wise youll get nothinng, or strange connection errors