PictureTel Concorde 4500 Servicing Manual page 125

Table 4-9: Technical Tips (Continued)
Component
Checking audio - far-end
or long distance
Switched-56 network
interface board
Network data rates
Private dialing network
X.21 Network Interface
board
Any local telephone company can arrange for you to
have a local network loopback number. If you call a
loopback number and get audio, there is a problem
with the long distance carrier or the far end.
To verify that you can call out of the building, you can
call the central ofÞce (CO). To Þnd out whether the
audio signal is getting out of the building, the
telephone company can put a trap on the line. If the
signal is not caught by the trap, then the signal is not
getting sent out properly by the data circuit-
terminating equipment (DCE).
If the two NS signals on the back of the CSU are lit,
you are not receiving any signals from the network.
A 56 kbps network cannot carry calls at 64 kbps,
which is what is required for ISDN services. Ideally,
your network should be able to operate at both 56
kbps and 64 kbps. Check with your network provider
for more information.
If you are using a private dialing network, for
example, a government network, you cannot call out
of your circle without using pic codes. Call your local
telephone company for information on how to get pic
codes for your service.
If you are upgrading your system and using a new
X.21 interface board, be sure to order a network
conversion kit when you order your network board. If
the system you are upgrading has a CP board (part
number 500-0070-02) revision M or older, then you
also need to order an upgrade kit that includes the CP
board.
Technical Tips
Tip
4-27