So my childhood PC that I got in yesterday has 2 COM ports. COM1 works fine. COM2 does not. Any ideas? I checked the BIOS: I can turn it on or off. There are no ISA cards installed so IRQ 4 is free. I am going to try PC Tools now.
What device are you using to test the port? If you're using a 25-pin to 9-pin adapter, are you sure it's not a null adapter with crossed wires?
Have you checked to see if the port is physically connected to the motherboard?
1: It is physically connected.
2: Tried a 25PIN serial mouse.
3: PC Tools confirms controller & IRQ work.
4: Port is physically embedded in MOBO.
5: Next step: buy loop back test plug and test again with PC tools.
wrote:2: Tried a 25PIN serial mouse.
I'm amazed you managed to fine one! But have you tested that on another computer to make sure it is working?
5: Next step: buy loop back test plug and test again with PC tools.
Good idea. In theory you can manage with just a paper clip if a 25-pin loop back test plug proves elusive.
I have 2 25PIN serial mice that work just fine. They are pretty common on eBay USA and you can get them pretty cheap usually.
How does the paperclip work? What pins would I connect? 😊
I think you might be able to get away with connecting pin 2 to pin 3, but I have no idea about how thoroughly PC Tools tests the port. See for instance http://digital.ni.com/public.nsf/allkb/B9A389 … 62572C7005F0644 and http://www.ni.com/white-paper/3450/en/ .
Needless to say, it's a whole lot easier to connect the pins if you have a 25-pin female connector.
Thank you Sir!
Ordered a female/female converter from Amazon. Once that arrives I can try the loop back test. 😀
Built the loop back test device with a F/F 25PIN converter.
Verify Controller = Passed
Handshaking = Failed
Loop-back = Passed
Interrupt = Passed
Interesting: with the proprietary mouse driver that came with the BIOS diskette the mouse works on COM2. 😊
