CN-1108 Setup and Installation Manual
12
10.
AUTO NOISE LEVEL FUNCTIONALITY
Auto Noise Level Adjustment is a very useful feature in CN-1108 when installing
under noisy line or old wiring conditions. The unit can automatically compensate for
noise within the line by analyzing the signals of each port and adjust its noise floor
accordingly.
You can turn on/off the Auto Noise Level feature through the ICD command
interface via Console or Telnet. The commands to activate and deactivate this feature
within the ICD command interface are “AO” and “AF” respectively.
Occasionally you will find that the Auto Noise Level feature unable to compensate
for the noise in certain lines. This phenomenon is usually caused by surrounding noise
lines or bad wirings (high impedance). Signs of trouble with the noise floor would
indicate by excessive collisions on the affected port, or loss of link status with a sudden
gain in status.
Noise level threshold can be adjusted manually through console by changing the
register value; Register 25 is to record the setting of noise level, while register 23 is to
write/change the value of noise level.
Through Register 25 we may monitor the signal peak and noise level. Type
rr25
in the command line for Register 25 values:
Figure A
PC01 indicates port 1, PC02 indicates port 2, PC03 indicates port 3, etc. R25: indicates
register.25, for 0CFF; the first two digits (0C) indicates the noise level, which is the
default value of CN-1108. The second two digits FF indicates the peak signal level,
usually range from 30 to 60 hex (4A to 58 as shows). FF indicates no connection of that
port.
