Centralized audio applications
4.10 EST3 Installation and Service Manual
URSM Universal Riser Supervisory Module
The Universal Riser Supervisory Module (URSM) provides open
and short circuit, and amplifier supervision of two risers, audio
(25 or 70 Vrms), and/or firefighter telephone riser. A form C dry
relay contact is provided for each riser circuit’s trouble
annunciation. Ground fault detection is also provided for the
risers using a GFD Ground Fault Detector.
Figure 4-5: URSM
Application
The URSM is required on 70 Vrms audio system risers, and 25
Vrms audio systems. The URSM should be located in an
equipment cabinet convenient to the end of the risers, which has
24 Vdc power available. URSM trouble contacts should be
monitored with a SIGA-CT2 module to signal riser trouble
information back to the network.
The URSM riser inputs should be connected to a GFD, which
provides ground fault monitoring. The GFD should be monitored
with a SIGA-CT1 module to signal riser ground fault conditions
back to the network. The GFD and SIGA-CT1 must be installed
in the same enclosure and should be located adjacent to the fire
alarm control panel.
Table 4-4: URSM specifications
Voltage 24 Vdc
Standby Current 40 mA
Trouble Contact Rating 30 Vdc @ 2A
Trouble Detection Levels
25 Vrms audio
70 Vrms audio
Firefighter’s phone
10 Vrms
23 Vrms
2.7 Vrms
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