4-14
Diagnostics
GDC 048R154-000
Local Test with Self-Test checks the internal circuits of local DSU
isolated from both the T1 line and the DTE. It does not check the
channel interface to the DTE.
To initiate the test from the Diagnostics Selection screen, select
[6]
Start Network Local Test with QRSS Self Test
.
Figure 4-10
Data Path for Network Local Test with Self Test
Network Remote Test
The data path for the Network Remote Test is illustrated in Figure 4-
11. You can command the loopback by means of either the terminal
interface screen or the front panel switches.
When you initiate a Network Remote Test the DSU transmits a loop-
up code to the remote unit for approximately five seconds. The remote
unit responds by engaging either a Line or a Payload loopback
(determined by its optioning).
After the loop is established, connect test equipment to the local DSU
DTE interface. Generate a test message. The test equipment should
receive back the same message it transmits. A problem exists if it does
not.
Network Remote Test with a Line loopback tests the line and the
network interface at the remote DSU. Network Remote Test with a
Payload loopback extends the test to include network interface
circuitry at the remote DSU.
TPG – Test Pattern Generator
TPC – Test Pattern Checker
DeskTop T1 DSU
DTE
Interface
Network
Interface
TPG
TPC
