Lava's serial port may bring 56-kilobit/sec modems closer to speed
The summer doldrums are over, so you won't be reduced to reading my long-threatened
column about cute things my dogs have done.
An interesting new product that might boost the disappointing performance of the new
56-kilobit/sec modems and other serial port devices is the LavaPort 16650 UART, a
chip-based serial port from Lava Computer Manufacturing Inc. of Rexdale, Ontario, Canada.
Visit the company's World Wide Web site at http://www.lavalink.com.
Although the 16550 serial controller UART chip found in most of today's computers can
handle up to 115.2 kilobits/sec, all modems can compress that data stream. Lava contends
that even 33.6-kilobit/sec modems can benefit from a faster serial port.
After some testing, I found Lava's claims held true, even though 56 kilobits/sec is not
achievable in the real world because of imperfect line connections.
If you've missed the 56-kilobit/sec battle, here it is in a nutshell: Two industry
groups have been squabbling over a standard for dial-up modems that theoretically could
download as fast as 56 kilobits/sec and transmit at V.34+ 33.6-kilobit/sec speed upstream.
The claims have proved hollow. The 56-kilobit/sec modems give only a marginal
improvement over 33.6-kilobit/sec modems, which mostly drop down to 28.8 kilobits/sec or
less over ordinary connections.
Apparently even the manufacturers know 56 kilobits/sec is unrealistic. They haven't
been lobbying for the Federal Communications Commission to drop an old rule that makes it
illegal to send data faster than 53.3 kilobits/sec over regular phone lines.
If 56.6 kilobits/sec were achievable, these modems would all break the law. But don't
panic, no one is going to get speeding tickets for using modems that follow Lucent
Technologies Inc.'s K56flex or U.S. Robotics Corp.'s x2 protocols.
Compressed data speeds are irrelevant here. The numbers refer to actual data
throughput, not to the total compressed data that moves over phone lines.
About 100 kilobits/sec of data will compress down to only about 33.6 kilobits/sec in
the modem, then expand at the receiving modem, so neither real-world line limitations nor
FCC rules get violated.
My tests showed little difference between K56flex and x2 modems for ordinary data
exchanges. However, the x2 modems markedly outperformed K56flex models at high compression
If you need to specify a modem, I recommend U.S. Robotics' Courier V.Everything,
Motorola Mobile Computing Products' VoiceSurfr 56K or the Zoom/FaxModem 56K from Zoom
Telephonics Inc. of Boston.
Digital video disks have run into a roadblock. Big players Sony Electronics Inc.,
Hewlett-Packard Co. and Philips Electronics Inc. have chosen to go with a new DVD-RAM
recordable standard that will compete against the previously accepted standard for
With some companies just introducing their CD-RW drives this summer, it is conceivable
that this move had more to do with slowing down DVD and helping the CD-RW market than it
did with a real necessity to store 3G instead of 2.6G on a DVD.
Fast acceptance of DVD-writable, formerly expected in mid-1998, would definitely kill
the CD-RW market.
Once DVD players become popular, will DVD-W be far behind? Can you think of another
reason why these companies would cut their own DVD throats by raising standards questions,
real or imagined, just as the DVD market is opening up?
If you can think of a reason, e-mail me with the word "paranoid" in the
Close on the heels of the other three companies, NEC Technologies Inc. has just
announced its own standard for a 5.2G rewritable format that would hold two hours of video
on a DVD-MMVF, or multimedia video file DVD.
Stay tuned--this battle could be important.
John McCormick, a free-lance writer and computer consultant, has been working with
computers since the early 1960s. E-mail him at email@example.com.