Emergency Command Center Manual —
P/N LS10001-000FL-E:D 9/3/2014
47
ECC-50DA, ECC-125DA, ECC-50BDA Distributed Audio Amplifiers
Installation
2.10 ECC-50DA, ECC-125DA, ECC-50BDA Distributed Audio
Amplifiers
SW2 on the ECC-50/100’s display board must be set to the UP position if
any
remote audio boost-
ers are installed on the system. Refer to the
ECC Distributed Audio Amplifier Manual
, LS10027-
000FL-E, for installation instructions.
2.11 Shielding for External Device Wiring
The external data bus and external audio riser circuits must be wired using twisted pair cable.
Shielded cable is optional but is recommended for sites with electric machinery, electric motors,
etc. to minimize the effects of electrical interference. Do not run either cable adjacent to or in the
same conduit as 120 VAC service, noisy electrical circuits that are powering mechanical bells or
horns, speaker circuits, motor control circuits or SCR power circuits. External operator interface
power (24VDC) may be run adjacent to or in the same conduit as the external data bus and external
audio riser circuits.
At the ECC-50/100 unit, the cable shields must be connected to the same connectors where the sig-
nals originate. If only one external device (i.e. an ECC-RM) is used in the system, the shield in the
external device must be left floating. It must not touch anything. If multiple external devices are
used in the system then the shields must “pass through” (connect to the outgoing shield using wire
nuts without touching anything else). For Class A (Style Z) installations, the shield from the last
external operator interface must be connected to the same ECC-50/100 terminal that the shield
originated from.
NOTE:
Never use a cable shield as an enclosure's earth ground. The EIA-485 shield is for
radiated noise emission protection (RFI, EMI).Refer to the following illustrations for details on
shield termination.
ECC-50/100
ECC-50/100
ECC-RM
ECC-RPU
ECC-LOC
ECC-50DA
ECC-125DA
ECC-50BDA
Class B
(Style Y)
Class A
(Style Z)
External Data Bus or
External Audio Riser
External Data Bus or
External Audio Riser
Figure 2.28 Shielding for One External Device
sh
ld
si
ng
le
.w
m
f
ECC-RM
ECC-RPU
ECC-LOC
ECC-50DA
ECC-125DA
ECC-50BDA
