3Com NBX 100 Administrator's Manual page 204

204 C 3: D
HAPTER EVICE
C
ONFIGURATION
4 Scroll through the Member List to verify that all 23 channels are present
for each T1 Digital Line Card in the system.
Completing the T1 Configuration (DS1)
To complete the T1 installation:
1 On the Digital Line Cards tab, select T1 Channel List from the Select
Device Type list and click Apply.
2 Wait approximately 30 seconds for the status of each channel to change
from Ready to Idle.
Click Apply to refresh the list of channels and to see the updated status. If
you have connected the Telephone company's T1 line to the T1 Digital
Line Card, the Nominal (3C10116C) or the CO (3C10116D) status light on
the front panel of the T1 board should now turn on (solid green). If the
status light does not turn on and you have the telephone company's T1
line connected, disconnect the T1 line and connect a loopback connector.
If the light now turns on, contact the telephone company for assistance
with the T1 line. If the light does not turn on, contact 3Com Technical
Support.
Enabling and Disabling Echo Cancellation
There are two situations in which it may be desirable to disable echo
cancellation on a T1 Digital Line Card.
An NBX system is connected to a telephone carrier (Central Office) by
a T1 Digital Line Card, and the telephone carrier guarantees to provide
echo cancellation on all channels, all of the time.
Two NBX systems are connected together directly using T1 Digital Line
Cards and the network between the two is completely composed of
digital circuitry, thus eliminating sources of echo.
You can enable or disable echo cancellation for each T1 Digital Line Card.
You cannot enable or disable echo cancellation on individual channels.
Before you enable echo cancellation for a T1 Digital Line Card you must
verify that the card is configured for DS1 operation and not ISDN PRI.