Modem facts you should know

Dialing up a network

Modems don't hold the vaulted position on the Core Hardware exam they have in the past, but expect to see questions on the exam about installing, configuring, and troubleshooting a modem, both internal and external.

Modem facts you should know

A modem (which is an acronym for modulator/demodulator) converts the digital data signal of the PC into the analogy data signal used on the plain old telephone system (POTS), which is also called the public telephone switched network (PTSN). Modems can be installed inside the PC in an expansion slot or attached to the PC externally through a serial or USB port.

You may hear or have heard of modems for other types of communications besides dialing into a network, such as an ISDN (Integrated Services Digital Network) modem or a DSL (Digital Subscriber Line) modem.

Modem types

The two general types of modems are the following:

l Standard modem: A standard modem can be an internal or external device. It can also be Plug and Play or legacy. Standard modems are operating system neutral and use generic device drivers.

l Windows modem: A Windows modem is an internal Plug and Play device that requires a device driver provided by the Windows operating system to function properly.

The best way to differentiate one type of modem from another is by reading the documentation that came with the system or visiting the manufacturer's Web site.

Internal versus external modems

An internal modem is installed like any other expansion card--into a compatible expansion slot. Modern modems do not require physical configuration, but some have DIP switches or jumpers to be set. Most of the configuration of the modem is done through the operating system.

Modems use serial communications modes. Be sure to read up on flow control and full- and half-duplexing.