Shelf Manager ACB-VI
Telco Alarms
19
R1.2, March 2018
14 Telco Alarms
The Shelf Manager ACB-VI can manage a Telco Alarm Interface with the following
components:
• Telco Alarm connector
• Telco Alarm LEDs
• Telco Alarm Cutoff push button
In Schroff Shelves these components are located on a separate board called Shelf Alarm Panel
(SAP). All three aspects of Telco interface are controlled by a PCA9555 located on the SAP.
The PCA 9555 is connected to the Shelf Manager via an I²C connection. The Shelf
management software running on the ShMM-700R is responsible for:
• configuring the PCA9555 as inputs or outputs, as appropriate for the Telco interface
signals.
• reading and writing GPIO port registers at appropriate times.
The PCA9555 generates an active low interrupt output when one of the inputs changes its
value. That interrupt output is routed on the ACB-VI onto the shared interrupt line going to
the INT# input of the ShMM-700R. Software running on the ShMM-700R is responsible for
reacting to an input change when an interrupt is triggered by the PCA9555.
For more information see the Chapter „SAP“ in the Shelf’s User Manual.