Verilink M1-3 (880-503136-001) Product Manual - Manual (Page 62)

M1-3 Diagnostics
5-6 Verilink M1-3 User Manual
Figure 5-8 DS3 Local Loopback
DS3 Line Loopback When a DS3 line loopback is activated, the data received from the
network is transmitted back toward the network. The looped signal
passes through the M1-3 repeater so that the line loopback can be
used to test the circuit from the far-end M1-3 or telephone
company (
Figure 5-9 ).
The M1-3 sends the network signal or AIS to the equipment,
depending on how the M1-3 is configured.
If network loopbacks are enabled, the line loopback can also be
activated by sending the industry-standard inband loop-up code
(00001) for at least 5 seconds to an M1-3. It is then deactivated by
sending the corresponding loop-down code (001) for the same time
period.
Figure 5-9 DS3 Line Loopback
DS3 FEAC Far-End
Loopback
The FEAC loopback is only applicable when in the C-bit mode. This
option is disabled when operating in M1-3 mode. When a DS3 far-
end line loopback is activated, the data received from the network
is transmitted back toward the network. The looped signal passes
through the M1-3 repeater so that the line loopback can be used to
test the circuit from the near-end M1-3 or telephone company
(
Figure 5-10 ).
The FEAC channel is a part of the overhead bits in a DS3 circuit with
C-Bit framing. Equipment in the telco cloud can interfere with the
loop-up signal.FEAC must be enabled at both ends of the circuit.
See Chapter 3 “
M1-3 Configuration Options ”.
The M1-3 sends the network signal or AIS to the equipment,
depending on how the M1-3 is configured.
M1-3 M1-3
Near End Far End
M1-3 M1-3
Near End Far End