Honeywell Farenhyt ECS Series - 3: VBUS Wiring

ECS Series Manual — P/N 151455:H 2/15/2022 33
Installing the ECS-INT50W ECS Device Installation
The internal amplifier must be powered by either a NAC programmed as constant auxiliary power or by an auxiliary power supply UL-listed
for fire protective signaling. Refer to the FACP installation manual for more information.
4.5.3 VBUS Wiring
The VBUS is an analog voice bus that carries the recorded voice messages from the ECS-VCM or ECS-NVCM to the ECS-INT50W ampli-
fiers, or the voice messages generated from a system microphone to the ECS-INT50W.
The maximum resistance on the VBUS is 20Ω.
SBUS
NAC
24V
–
–
–
+
+
+
AB
FACP
NAC programmed as
constant aux power
OR
UL-listed aux power
supply
ECS-INT50W
Figure 4.34 Wiring the ECS-INT50W to the FACP
supervised,
power-limited,
Class B