User guide

5-6 Solo E1 DSU User Guide—June 1998
5
The Loop DTE Test
The Loop DTE test veriÞes the operation of the DSU/CSU and the
associated DTE cabling and equipment by looping the E1 network transmit
signal through a 4 000 foot simulated line to the DSU/CSU network receive
circuitry (Figure 5-2 shows both Full and Fractional Bandwidth).
The DTE equipment should receive the same signal (a series of 1s and 0s) it
transmitted. The E1 network transmitter continues to transmit the pattern
toward the network while the DSU/CSU is in DTE loopback.
E1 payload transmission is interrupted during this test.
Figure 5-2 Loop DTE Test—Full and Fractional Bandwidth
CSU
Local Solo E1
Full Bandwidth
DTE
Network
Interface
DSU
Data
Port
CSU
Local Solo E1
Fractional Bandwidth
GR619
DTE
Network
Interface
Network
Interface
CSUDSU
DSU
Remote Solo E1
Data
Port
Data
Port