Communication Devices; Connecting A Modem Cable - HP compaq Hardware Manual

Connecting a Modem Cable

A modem cable, which has a 6-pin RJ-11 connector at each end,
must be connected to an analog telephone line. Jacks for digital
PBX systems may resemble analog telephone jacks, but are not
compatible with the modem.
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WARNING: Connecting the notebook to a digital line can
permanently damage the modem. Immediately disconnect your
modem cable if accidentally connected to a digital line.
If the modem cable contains noise suppression circuitry, which
prevents interference from TV and radio reception, orient the
circuitry end of the cable toward the notebook.
RJ-11 modem cable with noise suppression circuitry
Hardware Guide

Communication Devices

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