Comm prot question

[FSEdge]

Greetings, I am trying to use both Comm ports. Comm1 is used for the serial mouse. And Comm2 for the external modem. Comm port 2 appears to be bad on the motherboard. How can I determine if this is indeed the problem? I have tried switching both devices back and forth.
Any help would be greatly appreciated.

Thanks
FSEdge

 

[edfair]

When you say you have switched do you mean the addressing and irq? And that would be the way. You should be able to assign the addresses and IRQs to each port. And if second doesn't work as 1 then you have probably identified the problem Ed Fair
efair@atlnet.com

Any advice I give is my best judgement based on my interpretation of the facts you supply.

Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[FSEdge]

Thanks for the reply.
When I talk of switching. By this I mean the two devices at the Dsub9 connectors. Actually one is a Dsub9 connector and the other is a 48 pin. Not sure what you guys call it. I do have an adapter on it to allow for a Dsub9 female. I am not really sure how to handle the IRQs and the addressing. I have never had to change them in the past. If possible could you maybe point me in the right direction. I will have a go at anything on this machine. It would be a good learning exercise.
Thanks

FSEdge

 

[rtshort]

First I would check in the BIOS and make sure that both Com Ports are enabled and set to different address to avoid resource conflicts. Com 1 should be set to 3f8 IRQ 4 and Com 2 should be set to 2f8 IRQ 3. When an internal modem is used on Com 2 the Com Port is, strangely, set to Disabled. If you are removing an internal modem and installing an external modem, check this first.
You can turn the computer off and put the mouse on Com 2. If it finds the mouse when you start it, then Com 2 is working. Every day above ground is a GOOD DAY!!!

 

[edfair]

Connectors are D9p and D25p (not 48) for the number of pins , or 9s or 25s for sockets.
If they are not directly mounted on the board they likely will have ribbon cables to a set of pins on the board. Board header pins are usually 10 (2x5) and connected with a IDH connector with the pin 1 side of the ribbon at the same relative location on both headers. Ribbon headers can be put on the pins a pin off in either direction and cause the same problem. If you have ribbon cables connecting the M/B to the D connectors you can swap the positions on the board. Ed Fair
efair@atlnet.com

Any advice I give is my best judgement based on my interpretation of the facts you supply.

Help increase my knowledge by providing some feedback, good or bad, on any advice I have given.

 

[paulwood]

As edfair says it is worth while making sure the ribbon cables are properly connected at the M/B end, it's more likely than a duff serial port.