User guide
Diagnostics 5-7
5
Alternate Option
The signal sent is exactly opposite the signal sent in standard mode. This is
useful for testing a remote unit that has other equipment in between the
local and remote. The other equipment does not recognize the signal and
passes it through to the remote.
The Loop NET Test
The Loop NET test, available only on full bandwidth, veriÞes the operation
of the E1 network. (Figure 5-3).
It loops the data received from the E1 network back to the network. The
data is regenerated before it is looped back, however, the DSU/CSU does
not perform additional processing of the data.
This minimizes the impact of the DSU/CSU during the test so that network
problems can be isolated.
Figure 5-3 Loop NET Test
The Loop Payload Test
The loop payload test veriÞes proper operation of the DSU/CSU and the
E1 network (Figure 5-4).
NOTE: The DTE device must be able to recognize its own test pattern
for Loop DTE to verify the DTE cabling and equipment. Without this
capability, the Loop DTE test can only verify the DSU/CSU.
CSU
Local Solo E1
GR617
DTE
Network
Interface
Network
Interface
CSUDSU
DSU
Remote Solo E1
Data
Port
Data
Port