Re: Adding Serial Ports

Any of a dozen problems could be causing this, but the most common is that your jumper settings are wrong on the add-in card. You have to carefully set jumpers for both IRQ and COM port to use resources that are free under Windows. Moroever, you have to be careful that the card is not trying to use I/O ranges that are already in use by other devices, many of which are internal system devices that you wouldn't normally have to think about.

I would follow these steps:

1. Go to Device Manager (part of the System utility in Control Panel), find the device and tell Windows you are going to remove it. Shut down the machine and physically remove the card.

2. Boot Windows, go back into Device Manager, and get an IRQ usage summary to find out which ones are in use. As part of this same step, look at an I/O usage summary to find out which I/O ranges are already in use. These ranges are combinations of letters and numbers that look like E01F-E02G or something along those lines. This will be a long list and you may need to print it out.

3. Very carefully review the settings on your add-in board. You should have jumper settings for COM port number and IRQ, which you obviously need to get right. But usually there's a third jumper pad with settings for an I/O range. It will NOT necessarily work to just leave the default setting. You must carefully review the available options and pick a range that's free on your system. The instruction manual with the board should have instructions for all this, but of course a lot of those manuals are garbage.

4. After adjusting the jumpers, power down your system, reinstall the board and boot up again. Windows should recognize the presence of new hardware and offer to load drivers. Whether you can use the standard COM port drivers or need to use special drivers supplied on a disk depends on who manufactured the board. This, too, should be part of your instructions.

I have sometimes had to go through multiple jumper configurations to get these boards to work. Moreover, beware that Windows sometimes arbitrarily renames your existing COM ports; it seems to want them in some kind of weird order. So an auto-configurable modem that's now COM2 can easily become COM3 or COM4 when you add ports. This is usually not hard to deal with, you just have to tell any software that uses a particular port where to look for the device.

Good luck. It's probably becoming clear to you why people hate this legacy hardware and are pushing toward a world of USB and FireWire only.