At 11:00 AM 07/26/2000 Ira Wallin wrote:
>What are the pros and cons of external vs. internal modems?
>If an external plugs into the serial port, does that mean
>some other device can't be used?


Ira:

Here are some more advantages of external modems . . . .

1. You can reset external modems by powering them off and back on again.
With an internal modem, you have to shut down the entire operating system
and restart the computer to reset the modem, which is time consuming and a
bother in Windows.

2. It is usually easier to configure an external modem, since you are using
an existing COM port, usually a standard feature on the motherboard. With
an internal modem, you have to do one of the following:

  (a) share an IRQ (and plan not to use the other device whilst using the
modem);
  (b) use a non-standard IRQ, I/O port address and COM port assignment; or
  (c) disable an on-board serial port and assign its IRQ, I/O and COM port
to the internal modem.

COM port assignments are based upon I/O port priorities, not IRQs, and you
can become easily frustrated trying to configure a non-standard COM port
modem on a device-ladened system.

3.  There is a lower interference potential with the conversion circuitry
external to the system unit (this may only be theoretical, without
practical effect in a well designed computer).

An advantage of internal modems . . . .  External modems must rely on the
existing serial port.  Therefore, if you have a buggy or slow serial port
(such as those found on older motherboards without the latest UART chip),
then an internal modem will provide an UART chip upgrade in the bargain.

I would go for the external modem; the extra cost ($20 or so) is worth the
ability to reset the modem if it hangs.

HTH.

John Chin

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