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About V.90 56Kbps Connections
Initially when 56K technology was introduced, there was no industry
standard. Lucent Technologies, Rockwell International, and U.S. Robotics
each proposed their own protocols. Then, Rockwell and Lucent joined forces
to promote their K56Flex protocol, and U.S. Robotics released its own
protocol known as x2. In February 1998, the International
Telecommunications Union (ITU) released V.90 as a draft standard, with
approval expected in Fall 1998. The IBM 56K Modem supports both the x2
protocol and the draft V.90 standard.
56K modems take advantage of the fact that Internet Service Providers (ISPs)
and corporate networks typically connect digitally to the public telephone
system, enabling higher download speeds. Years ago, downloaded data was
converted from analog form to digital form then back to analog form again.
Today, it is now typically converted only once. That is, it travels digitally
from ISP to the telephone company, digitally between two phone company
offices, and finally analog to your modem. 56Kbps/V.90 modems use this fact
to treat the downstream communication path as entirely digital, allowing
faster download speeds. But that ability is only realized if your modem and
phone connection meet all the requirements as described in the following
paragraphs, and it only improves the downstream path. Data uploads to your
ISP will be 33.6bps or less.
There are several variables that will effect your Internet connection and your
ability to benefit from 56K technology. First your local phone system must not
make more than one analog to digital transition. Also modem speeds will be
affected by line noise, or interference, which is dependent on the quality of a
particular phone line. The maximum data rate available over regular phone
lines under the United States Federal Communications Commission's voltage
regulations for central office telephone equipment is 53Kbps. While 56K
protocol modems are capable of reaching download speeds near 56Kbps
under ideal conditions, speeds typically range from 40 to 50Kbps.
This modem includes both V.90 and x2 56K technology. To make 56K
connections, the modem requires that you connect to a V.90 or x2 compatible
Internet Service Provider. The modem will first attempt to make a V.90
connection. If this connection attempt fails, the modem will attempt to make
an x2 connection. If this attempt fails, the modem will attempt to make a
V.34 connection at the highest speed possible (up to 33.6Kbps speed).
2-2
56K Modem Internet Kit
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