3Com 000839-08 Manual page 10

Each COM port uses an interrupt request
(IRQ). An accessory uses an IRQ to get the
attention of your computer's centralprocessing
unit (CPU) so that the accessory can perform
a task. The computer stops what it's doing,
depending on the priority of the request, to
help the accessory perform its task. When two
accessories share an IRQ, it's like two people
asking different questions in unison to a third
person. Just as the person being asked the two
questions cannot understand either request, a
computer can lock up or otherwise fail to
communicate properly with your modem when
there is an IRQ conflict.
I M I
NTERNAL ODEM NSTALLATION WITH
W 3.
INDOWS X
D KEY POINT:
Accessories cannot
share COM ports and should not share
IRQs. When accessories try to share
settings, they will either not work
properly or not work at all. This section
of the manual will help you understand
the COM/IRQ settings on your new
Sportster modem.
U.S. Robotics has set your modem to a default
Plug and Play setting geared towards
Windows 95 users. In this configuration, the
shunts used to set your modem's COM port
and IRQ settings are hanging from single
jumper pins and will not affect your modem's
settings. As a Windows 3.x user, you need to
run the ComTest program (on the
Connections CD) to determine what settings
your modem should use.
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