The World of Modems

By Marco J. Shmerykowsky

So you want to get on the infamous Internet but can't decide which modem will get you there? Well, hopefully this little section of 'info will get you pointed in the right direction. With a little reading you'll be able to choose a modem which will be capable of handling the bandwith clogging graphics which are smothering the World Wide Web.

Modem Basics

Simplistically, a modem is a device which lets two computers communciate with each other. This is accomplished by Modulating / Demodulating the digital signal produced by the computer into an analog signal which can be transmitted along the Plain Old Telephone System (POTS) which is used by the telphone companies to handle voice communications.

Almost all modems have the same basic features beginning with supporting the Hayes AT command set. This is a series of commands which may be used to set the various features available on a particular modem. As the name implies, each of these commands is preceded by the letters "AT."

The other feature supported by modems include auto-answer, auto-dial, auto-disconnect, and automatic readialing. These features are known as telephone options. In general, these are features of convenience which help make telecommunication more user friendly

More important modem features include the type of supported communication (ie. half-duplex vs. full-duplex), error checking capbilities, self-testing, compatability, and speed. The first "feature" refers to the sequence in which a modem may communicate. In a half-duplex mode the modem can only send or recieve data. Although modern modems support more advanced communication methods, this type of communication is still useful if one must connect to an old mainframe (of which many exist) or if one is trying to track down a communications problem. In the world of computers, the method of "dummying up"a product often helps to identify problems. The "advanced communication methods" previously mentioned simply refer to "full-duplex" transmission which allow a modem to simultaneously transmit and recieve data.

An important point to consider when purchasing a modem revolves around compatability. Does the modem adhere to the "flavor of the month"? These flavors or standards are set by the Consultative Committee on International Telegraph and Telephony. Among this alphabet soup of standards are V.32bis, V.34, V.42, and V.42bis.

The V.32bis standard refers to modems which are capable of transmitting at speeds of 14,400 bits per second (bps). A mere five years ago this speed would have been considered blazing fast. Today, however, it is at the low, slow end of the market.
The newer standard is V.34 which allows for transmission speeds of 28,800 bps. Since the degree of compliance with this standard seems to vary between manufactures, one should exercise caution. Many modems are now capable of being upgraded to the flavor of the month through the use of software patches and flash EPROMS.
The V.42 standard refers to error correction. Since many users use the POTS lines for commuter communications, they must often deal with less than ideal line conditions. A modem should have the capability to compensate for poor connections. At some times, an automatically slowed down connection is preferable to the total loss of data.
The V.42bis standard covers data compression. Data compression allows a modem to increase its apparent speed capabilities by reducing the number of bits that are transmitted. Data compression capabilities explain why 14,400 bps modem can be set for higher transmmission rates such as 19,200 bps or 38,400 bps. It should be noted that the quality of compression depends on the type of data being transmitted. A simple ASCII text file, for example, may transfer at the fully compressed rate while a ZIP file may transfer at a zero compression rate. In general, the modem's compression abilities don't work well on files which are already compressed.

Two last points deserve to be mentioned. The first, which was somewhat covered during the discussion on compatablitity, centers on the modem's speed. Simply put, buy the fastest modem you're willing to pay for. As the internet grows in popularity, more and more people are creating WWW pages which are overburdened with graphical images. Since each of these images must be downloaded to the local machine, a slow modem may making "browsing" the WEB painfully slow. Also, don't bother waiting for the "faster" class which is "coming." Since speeds are always increasing, you may end up perpetually waiting.

The second point covers whether to purchase an internal or external modem. Internal modems are good becuase they contain their own 16500 UART chip. This chip has extended buffers which are needed for handling the fast transmission of compressed data. External modems, on the other hand, connect to a computer's serial port. If the serial port doesn't have a modern 16500 UART chip, then the external modem may not work properly. Additionally, the external modems have a series of informative status lights. These are helpful becuase they allow the user to be aware of what the modem is doing. With an internal modem, it is difficult to determine if the modem is transmitting data or if an error has occured.

O.K. That should have covered the basics.....

Modem Manufacturers

This section contains links to some of the major manufactures of modems. This is a good starting point in your quest for a new modem. Things to consider are : 1) Upgradeability, 2) Speed, 3) External vs. Internal, 4) Software, Hardware, and Operating System Compatability, 5) Bundled Software, and 6) Price (of course!)

[IMAGE] Hayes Microcomputer Products -- This is the company that set the standard for computer modems. In fact, any modem you buy today most likely features Hayes AT command set compatibility. The WEB site provides a good deal of information about their various products. One of Haye's current 28,800 bps modems targeted at the home market is the Accura 288 V.34/V.FC + Fax.

[IMAGE] Motorola Information Systems Group. -- Motorola makes computer chips for everything these days. Among all of this stuff you can find some fairly good modems. In fact, PC Magazine recently rated the Power 28.8 Data/Fax Modem as an "editor's choice for serious users." With the demands poorly designed WEB pages are putting on modems these days, every 'Net user falls into this category. Definitely worth looking into!

[IMAGE] Zoom Telephonics, Inc. -- Yet another maker of modems. They seem to make average modems which have average performance and average features with prices a little to high to be average. They have a decent WWW site. Look into the Zoom.FaxModem V.34X

[IMAGE] U.S. Robotics Inc. -- This is a pretty good and popular modem manufacturer. If you get or buy a Telepath modem from Gateway 2000, then you're really getting a USR modem. A recent PC Magazine review placed the Sportster 28.8 V.34 Faxmodem as a superior performer in terms of throughput and ability to work with less than ideal phone connections.

[IMAGE] Multi-Tech Systems, Inc. -- Multi-Tech is known for producing "high-end" modems which tend to be geared to the power user. Consequently, novices may find their modems to be a little to difficult to handle. Their entry into the "home market" is the MultiModem MT2834ZDX. This modem comes with a Virtual Modem Driver which allows a user to run multiple Windows communications programs simultaneously. Be Warned about the Virtual Driver! Since VxD's are allowed to run in Ring 0 (the most "sensitive area" of an Intel CPU), a problem here can cause major problem with Windows stability. Also, forget about OS/2 since it doesn't support those dangerous VxD's.

[IMAGE] Best Data Profucts, Inc. -- Best Data's current offering for the home market is the SmartOne 2834FX Their WWW site seems to be well organized and has various product categories such as Macintosh modems, high speed modems, and voice modems.

[IMAGE] AT&T / Paradyne. -- Paradyne seems to offer decent performing modems at reasonable prices. The current entry into the home user market is the AT&T DataPort Express 28.8. The AT&T name carries weight, but they recently announced they're selling Paradyne. Don't know what will happen with their product line :(

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Please send comments, suggestions, and problem notices regarding this page to:
Marco J. Shmerykowsky.

Last updated on: 10 January 1996

	Hayes Microcomputer Products -- This is the company that set the standard for computer modems. In fact, any modem you buy today most likely features Hayes AT command set compatibility. The WEB site provides a good deal of information about their various products. One of Haye's current 28,800 bps modems targeted at the home market is the Accura 288 V.34/V.FC + Fax.
	Motorola Information Systems Group. -- Motorola makes computer chips for everything these days. Among all of this stuff you can find some fairly good modems. In fact, PC Magazine recently rated the Power 28.8 Data/Fax Modem as an "editor's choice for serious users." With the demands poorly designed WEB pages are putting on modems these days, every 'Net user falls into this category. Definitely worth looking into!
	Zoom Telephonics, Inc. -- Yet another maker of modems. They seem to make average modems which have average performance and average features with prices a little to high to be average. They have a decent WWW site. Look into the Zoom.FaxModem V.34X
	U.S. Robotics Inc. -- This is a pretty good and popular modem manufacturer. If you get or buy a Telepath modem from Gateway 2000, then you're really getting a USR modem. A recent PC Magazine review placed the Sportster 28.8 V.34 Faxmodem as a superior performer in terms of throughput and ability to work with less than ideal phone connections.
	Multi-Tech Systems, Inc. -- Multi-Tech is known for producing "high-end" modems which tend to be geared to the power user. Consequently, novices may find their modems to be a little to difficult to handle. Their entry into the "home market" is the MultiModem MT2834ZDX. This modem comes with a Virtual Modem Driver which allows a user to run multiple Windows communications programs simultaneously. Be Warned about the Virtual Driver! Since VxD's are allowed to run in Ring 0 (the most "sensitive area" of an Intel CPU), a problem here can cause major problem with Windows stability. Also, forget about OS/2 since it doesn't support those dangerous VxD's.
	Best Data Profucts, Inc. -- Best Data's current offering for the home market is the SmartOne 2834FX Their WWW site seems to be well organized and has various product categories such as Macintosh modems, high speed modems, and voice modems.
	AT&T / Paradyne. -- Paradyne seems to offer decent performing modems at reasonable prices. The current entry into the home user market is the AT&T DataPort Express 28.8. The AT&T name carries weight, but they recently announced they're selling Paradyne. Don't know what will happen with their product line :(