Nortel 4000 发行公告

300115-B Rev. A

    Remote Access Software Version 5.3 Release Notes

8

Rockwell has acknowledged several problems with K56flex in an A law
environment. These problems are in the K56flex protocol, and are
common to all K56flex platforms. It is expected that Rockwell will release
modem software that will correct this problem.

A weakness has been detected in PCM/CIA-based modems that include
the Rockwell chipset. These problems can result in poor quality
connections. In these cases, you might want to lower the connect speed
or disable K56flex. Refer to your modem manufacturer’s documentation
for the specific modem command to do this.

All 56K modulations rely on the client modem to determine the final
connect speed. In some cases, the speed selection algorithm used by
Rockwell-based client modems may select t a connect speed that is too
high (often 50K), and this may result in errors or dropped calls.

Problems experienced using ZOOM modems (such as errors or dropped
calls) can be reduced by lowering the maximum speed to 40K; this might
not resolve the problems completely, however. The problems can be
resolved by obtaining a modem software upgrade from ZOOM. All other
K56flex modems tested, including Hayes, MultiTech, and Motorola,
exhibit similar problems at speeds greater than 44K. You should limit the
maximum speed to 44K in all A law applications via the
%digital_modem section of the RAC configuration file.

Release 5.3 is not compatible with K56flex Version 1.0 or
earlier. Note also that your individual modem manufacturer’s
software version number may be different from the
corresponding version of K56flex.