Installing an external modem is relatively easy. You don’t even have to open the case. All you need is a flathead screwdriver and a modem cable. Your modem may not come with a modem cable, so check the packaging.

1. Turn off the computer. Take your modem cable, connect one end to the computer’s serial or USB port and the other to the back of the modem. Tighten the plugs in, usually by tightening the screws on either side of the connection. Make them snug, don’t strip the threads.


2. Now connect the modem to the phone cord to the wall. Plug this cord into the “line” jack on the modem. If you want to use a phone too, use the line that came with the modem and run it from the phone to the jack on the modem labeled “phone”.


3. Now plug the modem in to the wall electrical outlet.


4. Now, turn on the computer and the modem. If the lights on the modem are working, you are ready to install the software. If they are not working, doublecheck all the connections. If these are fine, you may have the wrong modem cable or a bad modem.


5. If your modem is plug-and-play, (most are) Windows will generally detect it for you and you just need to put the driver diskette or CD in the drive and follow the general routine for installing drivers. If the external modem happens to not feature plug-and-play, use the Add Hardware Wizard found in the Control Panel and use the diskette or CD to install drivers.

Speed Considerations on Really, Really Old PC’s (Generally does not apply)

If you’re planning on using a 28.8, 33.6, or faster external modem, make sure you have a 16550 UART, or Universal Asynchronous Receiver/ Transmitter. This manages the communication between your modem software and the modem. Your modem may be able to operate at 115,200 bps, but with a slower UART, like 8250 or 16450, you will have data loss at these transfer speeds.

You can check your UART through a number if different diagnostic programs. Most modern computers have an adequate UART. If you can’t find out, just keep this in mind if you have problems later.

If you do have an older UART, slow the software down. Choose 9600bps or 19200bps. Even if you have a fast modem, your software will then limit the modem to this speed.

The good news, though, is that internal modems don’t have to worry about this because they have an updated UART on the card. This overrides the one on your computer. Only external modems are limited by the computer’s built-in UART. The only way around it if it is limiting you is to buy a new I/O card.