July 2013 © British Telecommunications plc 2013
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Figure 8 - typical display cycling on a fully commissioned unit with a signal strength of
21, grade 04, and pin 4 in the alarm or open state.
Additionally “bL” (battery low), and t1 and t2 (test modes 1&2) may also be shown amongst the
“AL” listing.
Path Status
The state of the communication paths is indicated by the LED dots on the displays.
Figure 9 - Path status dots