Description of 56K

There are different standards regarding 56K technology.

•K56Flex.

Technology developed by Rockwell Semiconductor Systems and Lucent Technologies

•X2.

Technology developed by USR (US Robotics, now 3Com)

K56Flex and X2 are not interoperable.

•V.90 Standard.

In February 1998, The ITU-T (ITU Telecommunication Standardization Sector) agreed on the technical specifications for 56K modems (V.90) and has approved in mid-September, 1998.

But, the modem driver can be updated to resolve fine points of operation between different vendor's modems and unusual telephone line conditions.

1. Due to FCC limitations, speeds of 53kbps are the maximum permissible transmit power levels during download transmissions.Actual data speeds will vary depending on line conditions.

2.In order to use the 56K feature, be sure to check if the standards supported by the on-line service provider and the modem are identical.

If you use a PBX phone system, you can not connect using the 56K mode due to line loss.

Specification

•Data communications.

V.90, K56Flex, V.34+, V.34, V.32bis, V.32, V22bis, V.22, V.23, V.21 BELL212A

•Data throughput speed

56,000 bps ~ 28,000 bps (V.90, downstream only, step: about 1333 bps)

42 Using the Modem