A specially designed cable that allows a user to connect two
computers directly
to each other via their communicationsports (RS-232 ports). Null modems are
particularly useful with portable computers because they enable the portable
computer to exchange data with a larger system. Null modem cables have the Tx
(transmit) and Rx (Recieve) lines crossed over, thereby allowing data to be sent
from one device to the other. They are similar to a
crossover cable where it is
the CTS (clear to send) and RTS (ready to send) lines are crossed over.
Null-modem cables are used for serial port connections.
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