Digital Link DL600E, User Manual

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6-8 DL600E E1 Data Multiplexer UserÕs Guide
Loop Payload Test
The Loop Payload test veriÞes proper operation of the DL600E unit and
the
E1
network.
It loops the payload data received from the
E1
network back toward the
network. Before it is looped back, the data is regenerated and a new
framing pattern is inserted. Thus, the proper
E1
framing of the DL600E
unit and network can be veriÞed.
The individual channel Loop Payload loops a selected ÒfractionÓ of the
E1
signal toward the network. In this mode, the selected data is
corrected and the inband national bit is regenerated before the data is
looped back to the network. Receive and transmit clocks and data are
suppressed toward the
data
ports on the
DTE
channels. Payload service
to ports not in loopback is not affected.
Figure 6-4 Loop Payload Test
Loop Up Remote and Loop Down Remote Tests
The local DL600E unit puts the remote unit into network loopback by
momentarily transmitting the industry standard loop up code to the
remote unit. If the remote unit does not go into network loopback
within
15
seconds, a failure is declared and the DL600E unit stops
sending the loop up code. The local and remote unitsÕ loop code and
network parameters must
match
.
The Loop Up Remote test uses the industry standard set codes. Once in
Loop Up Remote , test patterns can be sent to verify the Bit Error Rate
(BER)
performance of the bi-directional
E1
network signal.
Use the Loop Down Remote test to terminate the remote loopback.
D
Note
: The full bandwidth loop up code puts the remote
DL600E unit in a full bandwidth network loopback. The
fractional loop up code puts the DL600E unit in a fractional
(per individual port) payload loopback.
DTE
DSU DSU
S
S
Network
Interface
DATA
Port
Network
Interface
Remote Solo E1 Encore Local Solo E1 Encore
DATA
Port