Hayes' 56-kilobit/sec modem comes close to its touted speed -

Modem speed and price wars are causing some casualties.


The first thing I noticed when I opened the box containing Hayes Microcomputer Products
Inc.'s external 56-kilobit/sec Accura 56K modem was that there was no serial cable.


I happened to have a couple of spare cables squirreled away, but buyers who expect
ready-to-install products should be aware that few modem makers include cables anymore. A
notation to that effect on the box would save customers some aggravation.


Installing the Accura under Microsoft Windows 95 took less than five minutes, including
a cursory documentation reading. Hooking the Accura up to a server running Windows NT
Network wasn't much more difficult but took some legwork.


There was no driver for Windows NT on the modem's installation disk. The menu choices
in the software mentioned only Windows 95 and Windows 3.x. I guessed the Win95 driver
would work for NT. Just to be sure, I checked the Hayes World Wide Web site. There was not
a single reference to NT drivers.


I tried the Hayes support number a half-dozen times over two days without success.


Barb Miller, director of customer service and technical support, told me that Hayes'
support staff was overwhelmed with calls from a trade-in promotion. She said callers
usually have to wait no more than three minutes and that she is recruiting more staff.


I had better luck e-mailing the query to Hayes technical support. After exchanging a
couple of messages, a Hayes representative confirmed that the Win95 .inf driver also
worked with NT.


Like any long-time modem user, I would have been surprised to find that the Accura 56K
could deliver the speed suggested by its name. After all, V.32bis 14.4-kilobit/sec modems
never delivered dependable 14.4-kilobit/sec connections, and V.34 modems seldom
transferred at 28.8 kilobits/sec.


But upgrading 14.4-kilobit/sec modems to V.34 was clearly worthwhile. Although the
theoretical 33.6-kilobit/sec rate was inflated, the actual relative rate was about twice
as fast.


The advance to 56 kilobits/sec has been less successful. I never got a 56-kilobit/sec
transfer rate when I tested the pair of Accura modems and didn't expect to see one. Here's
why.


Until fairly recently, modems were thought to be limited to a maximum of 33.6
kilobits/sec by a natural barrier described in Shannon's Law, which has to do with noise
on analog telephone lines.


But few telephone networks today are 100 percent analog. Most voice lines connect to
the telephone company's central switching system over digital lines.


Engineers devised ways to take advantage of this digital presence to achieve up to
56-kilobit/sec traffic downstream from the central office to the user. Shannon's Law
wasn't overturned; upstream traffic to the central office is still limited to 33.6
kilobits/sec.


There are two 56-kilobit/sec transfer protocols competing in the industry at the
moment. Hayes modems follow the Lucent Technologies Inc.'Rockwell International Corp.
K56flex protocol, which won't interoperate with x2, championed by U.S. Robotics Inc., now
part of 3Com Corp.


The Telecommunications Industry Association and International Telecommunications Union
aren't expected to establish interim standards for 56-kilobit/sec modems until the end of
the year.


In the meantime, several conditions must be met to achieve transfer rates faster than
V.34bis modems can deliver:


Here's a final shocker: Even if you meet all these technical conditions and are lucky
enough to get laboratory-clean connections, you still won't get 56 kilobits/sec
downstream.


Federal Communications Commission regulations on power consumption limit analog modem
speed to 53 kilobits/sec.


Although you can achieve advertised performance under controlled conditions, modems
never perform as well in the field because of noisy analog lines, long distances between
connections or poor line quality.


In real life, expect the Accura modem download rate to be from 42 kilobits/sec to 46
kilobits/sec. Once the Accura locks in, it keeps a consistent grip and stable transmission
speeds.


I installed Remote Access Service under NT and connected to it using Windows 95
dial-up. Without the benefit of a compatible server upstream, the modems connected and
held at speeds no slower than 28.8 kilobits/sec and usually better. The best was 33.2
kilobits/sec.


For most users, the added performance you can expect from 56-kilobit/sec modems isn't
sufficient to warrant junking V.34 or V.34bis modems. But if you're buying new modems or
replacing faulty ones, Hayes has a trade-in plan that makes upgrading attractive.


For a few more weeks, the company will take in trade any non-Hayes modem, in any
condition, and give you an internal or external Accura for $99. Trade in any Hayes modem
and pay $89. Street prices for Hayes internal V.34bis modems start at $109. So with a
trade-in, you can buy a K56flex modem for less than a V.34bis.


You're not alone if you suspect any modem you choose may be obsolete soon. Many
potential customers are holding out until interim standards arrive. Hayes has promised to
provide free flash ROM upgrades that will make Accura modems compatible with the standard.


As a footnote, I wish modem companies would spend a few extra pennies on documentation.
Hayes, like its competitors, combines documentation for several different models into one
scant and rather disorganized pamphlet.


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