Acre SPC42 - Star and Multi-Drop Configuration

All expanders/keypads are fitted with termination jumpers, as default, allowing termination on all the
devices. This is imperative for the spur (chain) configuration, as the jumper acts as a resisting terminator
cancelling echoes on the line.
Within the loop wiring configuration all expanders/keypads are fitted with a jumper, as default, allowing
termination on the device.
Spur configuration
Number Description
1 Controller
2-4 Expanders
9.1.3 Star and multi-drop configuration
NOTICE:See Examples of correct wiring on page41, Examples of incorrect wiring on page42 and
Shielding on page43 before starting the installation.
The star and multi-drop cabling methods enables takeover of existing wirings with four-core cables in
small buildings (typically homes) with low electrical noise environment. These wiring methods are limited
to the specifications below:
SPC42/SPC52 SPC53/SPC63
Max. expanders/keypads 8 16 (8 per X-BUS port)
Total cable length 200 m 200 m
NOTICE: The performance in star or multi-drop configuration wiring is limited due to non-optimal
conditions of the RS-485 bus specification (reduced signal quality due to multiple
receivers/transmitters in parallel with unbalanced terminating resistors).
SPC42/52/53/63 – Installation & Configuration Manual Wiring the system
© Vanderbilt 2023 38 I-200572
08.12.2023