Buying A Modem
Getting Online Through the Hype

Copyright 1996, 1997 by William K. Walker

"This 'telephone' has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us."
                                                                       -- Western Union internal memo, 1876
The auto industry and the computer industry have a lot in common. There's a lot of hype, they both try to dazzle you with "extras", and there are a lot of folks who tell you that "cheaper" doesn't mean, well, "cheaper." No surprise, then, when you see advertisements for modems that look like something peeled off the window of a car dealership. Buying a modem isn't nearly as bad as replacing the old junker, though -- as long as you stay focused on the basics.
     There are three things to worry about when you go looking for a modem: speed, quality, and whether to get an internal or external unit. For the vast majority of humanity, everything else in or on the box is irrelevant.

A Need for Speed 

These days (late 1996), "speed" means at least 28.8kbps (28,800bps-- see the sidebar note). You can save a few bucks -- not many -- by buying a 14.4kbps modem, but it's not worth it. Sure, if you're only going to spend a few hours per month doing a little email on the local freenet, even an old 2400bps clunker will do the trick but, if you plan on "surfing" the Internet or playing around on one of the commercial online services, a fast modem will pay for itself in time saved, convenience and reduced online fees. "User friendly" means "lots of graphics" and everyone is trying to be user friendly anymore. And, although a picture may be worth a thousand words, it also takes a lot longer to download to your computer. (OK, OK, the guy in the propeller beanie just asked about 33.6kbps modems. Read on.)

Pay for It or Pay for It 

All modems are not created equal. If you live in a country with a solid telephone system, you probably won't see much difference in performance between a cheapo and a more expensive modem but you will very likely encounter a difference in reliability. Cheap modems don't last as long. I've seen some real dogs that died in less than a year. There's a pretty tight relationship between price and quality. And quality doesn't cost that much more -- less than $50 in most cases. I won't cast aspersions on any specific manufacturer but, if you see two 28.8kbps modems on the shelf, one produced by Xyzzy Corp. for $99.95 and the other made by, say, Practical Peripherals (PPI) for $20 or $30 more, buy the PPI unit.


While you are wandering around the store, you'll also notice that modems come in two basic flavors: internal and external. (Sounds vaguely obscene, doesn't it?) As you might expect, an internal modem is installed inside your computer whereas an external modem is cabled to an extra serial port and sits next to the machine in some convenient spot.
     Most folks buy internal modems. Physical installation is a mild hassle, but they typically cost $20 to $50 less than external modems, you don't have to worry about serial port performance issues and you don't have an extra piece of gear cluttering up your desk top.
     On the other hand, external modems have two big advantages over internal devices: The display panel lets you see what's going on and, if a dial-up session gets really snarled up, you can turn off the modem instead of rebooting the whole computer. However, you must have a spare high-performance serial port (see sidebar on UARTs). If your serial port is not up to snuff, you can't run an external modem reliably at speeds much above 9600bps. If you don't know what type of serial port your computer has, find out. A lot of people have gotten burned by this one. MS-DOS and Windows users can boot to MS-DOS (do not use a DOS prompt from within Windows) and run a program called MSD. If MSD says you have "16550A" serial ports, you're OK. If not, either buy a high-performance serial card (another $30) or get an internal modem. And you need to buy a shielded serial cable, too, by the way -- a $5 to $10 investment.
     All that being said, I like external modems. I spend a lot of time online and like being able to see what's happening on the phone line. Internal modems give me a pain in the nether regions but, then, I'm not exactly a "normal" user, either. It's your call (pun intended).

A Movable Beast 

What about modems for portable computers? Well, PCMCIA card modems are subject to the same speed and quality issues as conventional modems. There are only two significant differences: They cost more and they are all, in effect, "internal."

A Word or Two About "Extras"... 

Fax modems - These days, saying "fax modem" is like saying "new car with air bags." It would be most unusual to find a decent high-speed modem without fax capability.

Software - Just about every modem is sold with a generous handful of software of problematic utility. If you can't decide between two different brands and one includes a software package you like, buy that one. The only important question here is whether or not the modem is already supported by your operating system. If not, then make sure the manufacturer supplies the necessary drivers and utilities.

"Modem" stands for MOdulator / DEModulator. It's a hunk of circuitry that takes digital data from a computer and converts (modulates) it into a signal that can be sent across a telephone line to a modem hooked to a computer somewhere else. It also converts (demodulates) the signal from the remote computer's modem into data that can be understood by your machine. In other words, it lets two computers talk to each other over a phone line that was originally designed for voice.

You'll often see modem speeds specified in "baud" or "bps." For all practical purposes these days, the two terms are equivalent -- 28,800baud is the same as 28,800bps. "Bps" stands for "bits per second," it's the number of bits a modem can send or receive in one second. Wouldn't characters (or bytes) per second make more sense? Sure, but a bigger number looks better on the outside of the box. To get characters per second, just divide the modem speed (also called the "baud rate") by 10. So, 28,800bps is 2880 characters per second -- still pretty darn fast when you think about it.
     Curiously, the term "bps" is seldom used in conversation -- probably because it's easier to say "bawd" than "bee pee ess."

A UART is a chip that handles the serial port on a computer. (If you must know, UART stands for Universal Asynchronous Receiver - Transmitter.) Most modern IBM-style PCs have two serial ports, one for the mouse and the other for an additional "serial device" such as an external modem. Up-to-date machines have "high performance" serial ports operated by circuitry that looks like an NS16550A UART (also known simply as a "16550A" -- the "A" is important). If you don't have a 16550A-style serial port, you can't handle a high-speed external modem properly.

If you have poor quality telephone lines, you need a high quality external modem. As a general rule, a top of the line modem from a very reputable manufacturer will do a better job of handling line problems than an "economy" modem. It's also a very good idea to get an external modem. It will give you more information on line conditions than an internal modem and do a better job of isolating your computer from line voltage fluctuations. A "top drawer" external modem from an outfit like Practical Peripherals, Motorola or US Robotics can be an expensive proposition, but a cheap modem is likely to perform poorly and have a short lifespan.

There are many different ways modems can talk to each other. The reason this doesn't result in a sort of electronic Tower of Babel is because the various manufacturers adhere to a set of international standards or protocols. These are the "V numbers" you'll often see displayed prominently in modem advertising. For instance, V.34 is the protocol for communicating at 28.8Kbps. So, if a modem "does" V.34, this just means it can talk to another modem at 28.8Kbps. Other "V numbers" you are likely to see are V.34 annex 12 (33.6Kbps) and V.32 (14.4Kbps). There are at least seven more of these "speed" protocols, not to mention a whole grab-bag of standards for data compression, error correction and fax transmission, but they usually only show up in the fine print.

33.6kbps modems - The extra speed is nice, but not a critical issue. The 33.6kbps protocol (known as V.34 annex 12, if you really care -- see the sidebar on protocols) has recently become an official standard. If your local service provider has dial-in lines at this speed (mine does) and if your phone lines are clean enough to handle it, it's nice to have. Over the next year I imagine that all of the modem manufacturers will either upgrade their existing 28.8kbps models to 33.6kbps or bring out "new" models, dropping the price on the old ones.
     Better yet, many of the newer 28.8kbps modems are field upgradeable to the higher speed -- i.e., they just need to be reprogrammed. Typically, the upgrade package is a free download from the manufacturer's web site or bulletin board system. (Or they'll send it to you on diskette for a nominal fee.) The package includes an application that reprograms your modem to handle 33.6kbps and some updated files for your operating system.

56kbps modems - [Updated 10 Mar 97] Speaking of upgrades, 56kbps modems are looming on the horizon. Expect to start seeing this capability in early 1997. Remember, though, that these higher speeds are somewhat academic to a lot of folks. Without a first-rate modem and a pristine telephone connection, you'll be lucky to do any better than 28.8kbps. Furthermore, your local telephone office must use digital switching. If they are still using the old electro-mechanical switches (not uncommon in rural areas), you can forget about 56kbps.
      Here's another little detail: These 56kbps modems aren't really 56kbps modems. Right now, it looks like we'll get around 53kbps incoming and 33.6kbps outgoing. This is still a pretty good deal -- most people spend a lot more time doing things like viewing web pages than uploading files -- but the "56k" designation is still a little deceptive. Mind you, the engineering types originally thought that they would get 56kbps, so don't start sending nasty-grams to the manufacturers.
     Speaking of manufacturers, there are presently two competing "56k" standards. US Robotics and their allies are pushing one approach while another group is betting on the Rockwell chipset. So, be warned. "Early adopters" (myself, for instance) are only going to see "56k" speeds if they connect to a modem that uses the same 56k protocol. If you don't want to put up with this hassle, wait until the standards shake out.

Plug and play - PnP is a nice feature; potentially, it lets you avoid some configuration hassles. But don't let it divert you from the basics. A good modem without PnP is a better buy than a cheap one with PnP. Automatic device configuration is definitely the wave of the future, but it's not a tsunami yet.

Voice mail - Private voice mail capability could be rather handy, especially if you are running a small business. There are a few significant caveats here, though: You need the appropriate type of distinctive ringing to discriminate between data, fax and voice calls, you probably need a good chunk of free hard drive space to store incoming messages, you must have sufficient computer horsepower, and you have to leave your computer on all the time. There is also a fair bit of open territory in the area of software support. How well, for example, does the voice mail software coordinate with your existing dial-out applications? It will cost you an extra $30 to $60 to find out. Voice modem standards have not shaken out yet. If you just want to climb on the net and maybe do some faxing, save the extra money and send it to me, instead.

Modem Mantra 

So, here's the basic modem mantra: "speed, quality, inside or outside." Chant this under your breath as you browse the latest catalog or wander through Fast Freddy's Computer Barn and you won't go too far wrong. I wish I had something like that for used cars.


There are a lot of modem manufacturers and vendors out there. I've found that the best place to start looking for them is the list of links maintained by Yahoo:

Yahoo - Business and Economy-Companies-Computers-Peripherals-Modems

Many thanks are due to the following "beta testers" who provided many useful suggestions and a much needed sanity check:

Greg Chapman     David Freeman     Sandy Garrett     Neil Krandall

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Maintained by William K. Walker
Copyright 1996, 1997 by William K. Walker
Last update: 10 Mar 97