Chapter 5 - Troubleshooting and Diagnostics HCD-E1
Installation & Operation Manual
5-24 Diagnostic Tests 01/01/01 08:15
During the loopback, the DTE connected to the E1 sublink of the local
HCD-E1, continues to receive data.
LP R R SL
This remote remote loopback towards the DTE connected to the E1 sublink
of the local HCD-E1 is performed by connecting the transmit signal of the E1
sublink of the remote unit (output from the remote HCD-E1) to the input of
its receive path (input from the remote HCD-E1) within the sublink line
interface circuits, as shown in Figure 5-5. The test signal is provided by the
equipment connected to the E1 sublink of the local HCD-E1, that must
receive its own transmission without errors while the loopback is activated.
Figure 5-5 LOOP R R SL Loopback
This test checks the connections to the equipment connected to the E1
sublink of the local HCD-E1, all the circuits of the remote unit, the functions
of the remote and local units, and the transmission path between them.
During this loopback, the DTE connected to the E1 sublink of the remote
HCD-E1 continues to receive data.
Note
The following loopbacks (LP L CH, LP R CH, LP R R CH and LP INBAND CH)
are not recommended for HCD-E1 channel with Ethernet interface. Although
a channel loopback is not forbidden in principle, it may cause a state of
permanent collision on the LAN (this would prevent other users from using
the LAN as long as the loopback is connected).
LP L CH X
This local loopback on the data channel X of the local HCD-E1 (X can be 1
or 2) is performed by connecting the data channel transmit signal to the
input of the receive path, as shown in Figure 5-6. The test signal is provided
by the DTE connected to this channel of the local HCD-E1, which must
receive its own transmission without errors while the loopback is activated.
During the loopback, this channel of the local HCD-E1 continues sending
the user's data to the link.
This test mainly checks the connections to the local data channel interface.