An open circuit or short circuit on a power supply or network connection to one connected PT2009-A1 affects just this PT2009-A1. Other PT2009-A1 still work properly.
The figure below displays a redundant wiring example of multiple PT2009-A1 being connected to one cabinet. This wiring can be utilized in standard and evacuation use cases.
Cerberus PACE Compact cabinet
External 'Desk call station (RS485, 8+1)' PT2009-A1 with accessories
'MeanWell SD-50B-24 DC/DC Converter (50W)' PCA2011-A1 or 'MeanWell SD-100B-24 DC/DC Converter (100W)' PCA2018-A1
'Ground fault monitoring (24V)' PCA2001-A1
'ICPDAS I-7510 (RS485, isolated)' PNA2009-A1
'Call station interface (RS485)' PTO2008-A1
Wiring to PTO2008-A1
Copper Ethernet cable (CAT5) with RJ45 connector, connecting PTO2008-A1 to PT2009-A1
The two connected PT2009-A1 share one analog audio input channel. Therefore, only one PT2009-A1 can be active at the same time.
An open circuit outside the cabinet affects only the adjacently-connected PT2009-A1.
A short circuit at 'PACE-Bus' (RS485) or DC 24 V outside the cabinet affects only the adjacently-connected PT2009-A1.
A short circuit at the analog audio signals outside the cabinet affects all connected PT2009-A1.