3Com SuperStack 3 NBX Administrator's Manual page 294

294 C 3: D
HAPTER EVICE
C
ONFIGURATION
Completing the T1 Configuration (DS1)
To complete the T1 installation:
1 Return to the Digital Line Cards tab (Figure 113).
2 From the Select Device Type list, select T1 Channel List.
3 Click Apply.
4 Wait approximately 30 seconds for the status of each channel to change
from Ready to Idle.
While you are waiting, you may 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 or if you have connected a
loopback connector to the T1 card, the Nominal status light on the front
panel of the T1 board should now turn on (solid green). If the Nominal
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 Nominal light now turns on, contact the telephone company for
assistance with the T1 line. If the Nominal 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.
To enable echo cancellation:
1 In the NBX NetSet - Main Menu window, click Device Configuration.
2 Click the Digital Line Cards tab.