Unit installation

Chapter 6 Troubleshooting and Diagnostics FCD-E1 Installation and Operation Manual
6-20 Testing FCD-E1
LOCAL FCD-E1
E1 Sub
DSU
LTU
User DTE
E1 Sub
Figure 6-4. Sublink Local Analog Loopback
Sublink Remote Analog Loopback (LP REM ANA SL)
Local analog loopback towards the remote sublink. Performed by connecting the
sublink transmit signal to the input of the sub receive path within the sub line
interface circuits, as shown in Figure 6-5. The test signal is provided by the
equipment connected to the remote sublink, that must receive its own
transmission. During the loopback, the local FCD-E1 sends an unframed “all-ones”
signal to the equipment connected to the local sublink.
This test checks the connections to the equipment connected to the remote
sublink, all the circuits of the remote FCD-E1, the functions of the remote and
local FCD-E1, and the transmission plant connecting the two FCD-E1.
Transmission
Plant
User DTE
LOCAL FCD-E1
E1 Sub
DSU LTU
REMOTE FCD-E1
E1 Sub
DSULTU
User DTE
"1"
E1 Sub
Figure 6-5. Sublink Remote Analog Loopback
Sublink Remote Digital Loopback (LP REM DIG SL)
Remote digital loopback towards the remote sublink. Performed by connecting the
sublink transmit signal to the input of the sub receive path within the sub framer
circuits (before the transmit signal is applied to the line interface circuits). Except
for the location of the loopback, signal path is similar to that shown in Figure 6-5.
This test checks the same functions as the sublink remote analog loopback, except
that it does not check the operation of the analog sub-line interface.