Unit installation

Chapter 6 Troubleshooting and Diagnostics FCD-E1 Installation and Operation Manual
6-18 Testing FCD-E1
Before connecting this loopback on an FCD-E1 with an Ethernet port, disconnect
the LAN cable from the rear panel Ethernet interface.
LOCAL FCD-E1
E1 Sub
DSU
LTU
"1"
User DTE
Figure 6-1. Main Link Local Analog Loopback
This test fully checks local FCD-E1 operation, and the connections to the local
DTE.
During the loopback, the local FCD-E1 sends an unframed “all-ones” signal to the
remote FCD-E1.
When the sublink CGA mode is TRANS or NONE, and a sub local sync loss alarm
condition is present, the sublink sends an OOS pattern in the assigned main link
timeslots (for NONE it also sends the OOS SIGNAL pattern).
Under these conditions, it is not possible to perform BER testing on the sublink
when the local analog loopback is connected: if you try to measure the BER, the
result is invariably errors.
Main Link Remote Analog Loopback (LP REM ANA ML)
Locally performed analog loopback towards the remote equipment. Performed by
connecting at the local FCD-E1 the regenerated receive signal to the transmit input
of the main link interface, as shown in Figure 6-2. The test signal is provided by the
user's equipment connected to the ports of the remote FCD-E1: each one must
receive its own transmission.
This test checks the connections to the remote DTE, all the circuits of the remote
FCD-E1, the main link interface functions of the remote and local FCD-E1, and the
transmission plant connecting the two FCD-E1.
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e
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