When looking for a new modem, users usually don’t pay due attention to the choice. But while other components of a computer (for example, a latest and expensive video card or a processor) become obsolete very soon and require upgrade, the right modem will serve you many years. The quality work and whether a user is satisfied depends on how he is choosing a modem.

External modems

The device looks like a small plastic box with LEDs or Liquid Crystal indicators of the status. The modem is connected to a computer with an interface cable (RS232, LPT or USB, depending on the model), and is powered from the electricity supply network via an external power supply unit. Some external modems with a USB interface, unlike those with the RS-232, don’t require an external power supply unit – they are powered from the computer via a USB cable.

Advantages:
• Possibility to work with any computer which has the required type of an interface connector;
• Status indicators allow controlling the modem’s work;
• Its own power supply unit gives minimal pickups and noise from the internal devices installed in the computer;
• In case the modem hangs, it is not necessary to reboot the computer, you are only to restart the modem itself;
• You don’t need to open the system block, what is important in case of a warranty label on it, plus it is simple to install.

Disadvantages:
• Higher price of the modem due to the external case and a power supply unit;
• It is desired to use a UPS: power supply units of modems don’t ensure the quality work in case of severe changes in the voltage. Pulsed power supply units ensuring such work are used rarely in modems;
• Additional mains for connection;
• Necessity in a place in the system block, and sometimes obstructing interface and power supply cables;

Internal modems

Internal modems produced today are designed for ISA or PCI connectors and implemented in the form of a usual expansion card to be inserted in a slot of a mainboard. Besides, today you can find some models intended for a AMR/CNR connector.

Advantages:
• A lower price due to a lack of a case, a power supply and status indicators
• No need in additional connectors and power supply, and interface cables
• A free port for connection is not necessary

Disadvantages:
• Modem don’t have indicators of the status and working modes, what can bring about difficulties when defining possible problems of the operation;
• You have to make settings for the additional port to prevent possible conflicts with other devices in the system
• A power supply of a computer, as well as neighbour cards create additional noise which can prevent correct operation of the modem
• For a modem installation you are to open the system block and set (with the help of jumpers) a required port address and interrupt numbers if a modem is not compatible with the Plug-&-Play specification for modems via an ISA bus
• In case the modem hangs you have to reboot the whole system or even restart the machine