Number Description
1 SPC Controller
2-4 Expanders
Multi-drop configuration
NOTICE: All expanders/keypads are fitted with a termination jumper by default. In multi-drop
configuration it’s imperative to remove these jumpers with exception of last keypad or expander.
The multi-drop configuration varies in that each expander uses the same communication channel as it
wires onto the next expander, with all expanders using the same input channel. See multi-drop
configuration in the second figure.
In the case of a X-BUS break, all expanders and detectors up to the fault continues to be supervised. A
short in the cable renders all expanders disabled.
Multi-drop configuration
Multi-drop configuration 2
Number Description
1 SPC controller
2-4 Expanders
SPC4xxx/5xxx/6xxx – Installation & Configuration Manual Wiring the system
© Vanderbilt 2018 80 A6V10276959-d
11.2018