WebJunction

Before you go out and purchase a modem for your library's computer system, be sure that a modem is the most efficient way for you to access the Internet. If you are on a network (or there are more than five computers in your branch) and faster access (for example, xDSL or ISDN) is available in your area, there is probably a better and cheaper way to get online. See Choose Your Internet Connection for more information on your options.

If you are sure a modem is what your library needs, this guide can help give you an understanding of what to look for when you go to purchase one.

Basics

Telephone lines were designed to carry voices and sound, not the digital data that computers use for communications. However, years ago scientists seized upon the idea of using our existing telephone network to transmit data between computers instead of building a vast and costly digital network (which is the goal now). So a piece of hardware was designed to encode (modulate) the digital data into audio tones and decode (demodulate) the beeps and blips back into digital information. This piece of hardware is commonly referred to today as a modem (short for modulator/demodulator).

Performance

The best way to determine the performance of a modem is its data rate, also known as its bandwidth. Bandwidth is measured by the amount of data (images, e-mail, sounds) that can be transferred in a certain period of time. The "bps" used to describe modern modems is the number of bytes per second that it can transfer to another computer. A greater bps translates into a faster modem. Larger units, such as kilobit per second (abbreviated Kbps, equal to 1,000 bps) are used to denote high data speeds. One megabit per second (Mbps) equals 1,000,000 bps or 1,000 Kbps.

Here's how it works:

Everyone who has used a modem knows that it can take awhile to download images from graphical Web sites. If a Web site has an image that is relatively large, say 100 KB, the time it takes to download the image with modems having different bandwidths can vary greatly.

Today, most modems have a rating of at least 33,600 or 56,000 bps. You should contact your ISP to find out what rate they support, and choose the highest rate possible. A 56,000 bps modem will not do any good if your ISP only supports a 33,600 bps data rate. However, you likely will be hard pressed to find an ISP that cannot support a 56K modem.

Modems and fax

Modems are usually used solely for accessing the Internet, but they also can be used to perform a variety of common library tasks as well. One of the most useful features of newer modems is the ability to transmit faxes. This means that you can fax documents (or anything that you can print) directly from your desktop. Software is usually required, but there are some free programs available that are relatively easy to set up and use.

Types of modems

Internal

Pros: Cheaper

Cons: Can be harder to install for novices, hard to transfer to another machine

An internal modem is actually a card that fits into a slot inside of your computer. While installing a modem used to require a fair amount of tech savvy, plug-and-play technology now makes it a relatively simple task.

External

Pros: Very simple to install, can easily be transferred from one machine to another

Cons: More expensive

External modems are usually little boxes that you plug into your computer via its USB or serial port. Unlike an internal modem, you can transfer an external modem easily from one computer to another. USB modems do not require a power supply, unlike their serial counterparts.

"Soft" modems

Pros: Cheapest

Cons: Not cross-compatible

Winmodems and controllerless modems make up the category known as "soft" modems. These are generally the cheapest alternative because they let the computer take care of most of the processing work. Usually this does not make a difference in today's faster computers, but it can be a drawback on slower machines. Most of these modems are also designed solely for the Windows platform.

PC Card modems

Pros: Very small; suitable for notebook computers

Cons: Expensive

Also known as PCMCIA modems, PC Card modems are small enough to fit into a specially designed slot on many laptop computers. As external USB modems get smaller, they may become a cheaper, cross-platform compatible, alternative to PC Cards.

Wireless modems

Pros: Wireless

Cons: Expensive for speed

As more and more people buy laptops and PDAs, the demand for wireless modems has driven the technology to improve. While fast wireless modems are still expensive, there are cheaper PC card-like modems that can be used for downloading e-mail and text.