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Use caution when working with bare phone wires, as they may carry a current. In POTS, the phone company uses a battery to supply power to the line, which is sometimes referred to as self-powered. It isn’t truly self-powered, however, as the power comes from the phone system.


As a remote access connection method, POTS has many advantages, including:


■    It is inexpensive to set up. Almost every home in the U.S. has or can have a telephone connection.


■    There are no LAN cabling costs.


■    Connections are available in many countries throughout the world.


POTS is the most popular remote access connection method because only one primary disadvantage is associated with it: limited bandwidth and thus a limited maximum data transfer rate. At most, 64Kbps data transmissions are possible, though rarely achieved by the traveling user connecting remotely to the corporate network.

Integrated Services Digital Network (ISDN)


ISDN is a digital, point-to-point network capable of maximum transmission speeds of about 2Mbps, although speeds of 128Kbps are more common. Because it is capable of much higher data rates at a fairly low cost, ISDN is


becoming a viable remote user connection method, especially for those who work out of their homes. ISDN uses the same UTP wiring as POTS, but can transmit data at much higher speeds. But that’s where the similarity ends. What makes ISDN different from a regular POTS line is how it uses the copper wiring. Instead of carrying an analog (voice) signal, it carries digital signals. This is the source of several differences.

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