Testing
7-2
7925-A2-GB20-30
PRELIMINARY DRAFT
June 1997
Local Loopbacks
When local loopback is enabled the red Loop Bk LED on the front panel of the
initiating unit (CO or CP) lights up and remains lit until the loopback is disabled.
Figure 7-1 illustrates local loopback from a CO unit in a connection between two
units of the same compatibility (either two G.703-compatible units or two
V.35-compatible units).
Terminal
97-15249-01
CO
CP
E1 HDSL
7900
7900
E1 HDSL
7900
7900
Diagnostic
Equipment
Diagnostic
Equipment
Loop Bk
LED lights
Figure 7-1.
Local Loopback from CO End, Two Like Units
(both G.703 or both V.35)
Figure 7-2 illustrates local loopback in the same connection as in Figure 7-1, but
the loopback is initiated from the CP end.
Terminal
97-15518
CO
CP
E1 HDSL
7900
7900
Diagnostic
Equipment
E1 HDSL
7900
7900
Diagnostic
Equipment
Loop Bk
LED lights
Figure 7-2.
Local Loopback from CP End, Two Like Units
(both G.703 or both V.35)
