There are internal and external modems, there are regular telephone modems and ISDN modems, there are 2400 BPS thru 56KB/s modems. The variety is almost infinite, and you must decide.

In any case, you will need a telephone line of some type - either regular service or digital service (ISDN).

ISDN SERVICE:

ISDN Basic Rate Interface (BRI) is required for most ISDN modems or ISDN Terminal Adapters. BRI interfaces have 2 - 56KBPS channels (some say 128K total which is two 64KBPS circuity in the BRI package), but your throughput after overhead is 56KB per each channel. Some devices claim a much higher rate, but they use full duplexing techniques and compression.

ISDN lines are somewhat expensive. They may easily cost $40-90.00 per month per line for a home or business. In the Army, you would need to contact your DOIM to obtain an ISDN circuit. ISDN modems should give you much more throughput at a reasonable cost.

NORMAL PHONE LINE MODEMS:

If it is an internal modem, you must have an open expansion slot. If you do not have an ISA slot, don't buy an ISA modem. When adding a device into an expansion slot, you must have a free or usable IRQ. If attaching an external modem, you must have a free serial port.

Regular modems come in many speeds - older modems usually had speeds of 300, 1200, 2400, 4800, and 9600 baud. Newer modems have 14.4KBPS, 28.8KBPS, 33.6KBPS, and 56KBPS. There is some discussion that the 56KPBS does not really reach that level. Anything over 9600 uses some type of compression routines, but that is somewhat irrevelant to users. In today's market, I suggest that you purchase a 33.6 or 56kbps modem. Internet access is available at lower speeds, but the 14.4 for home use is too slow for many people, and is gradually disappearing from the shelves in most stores. Personally, I prefer an "interal" modem card but usually you need either an ISA or PCI expansion slot available.

For LAPTOP PCs, you can purchase a PCMCIA or PC CARD with 33.6 modems in the cards, and most are Windows 95 ready, and most include some "mobile" type software.

REMEMBER: If you are connected to a WAN, through a LAN, you probably won't need a modem. However, if you dial-in, or dial-out, using phone lines, you will need some type of modem.

IF you have a business with multiple PC's accessing the Internet, you may want to purchase a device called a "modem pool" which can allow you to connect 8 or 16 devices to the device. They can cost anywhere from $2000 to $7000.00.

There is a WEB Site "www.3com.com" that is invaluable for those who want ISDN or other types of devices and connections.