Wegener UNITY4000, Instruction Manual, Page: 24 / 75

UTY4000-003 2-10
2.5.1 Balanced Audio Outputs
There are two audio channel outputs on the rear panel. Each Channel (Ch1 & Ch2) has a right
and left mono pair. Each of these pairs is a balanced, low-impedance audio output, with
terminals labeled “+, -, and com.” These are accessed through terminal strips which plug
through the rear panel into the main PWB. These strips have screw terminals which accept
standard audio cables.
Please note that audio should be terminated with 600-ohm loads for correct output levels.
2.5.2 FCC-Mandated Suppression of Radiated Emissions
2.5.3 Alarm Relay and Addressable Contact Closures
The rear panel has an alarm relay and two network-controlled solid-state contact closures
addressable from the COMPEL™ uplink computer. The alarm relay’s “alarm” conditions are
the same as the front-panel ALARM LED. The alarm relay is factory-set so that an alarm
condition or the loss of unit power will cause the rear panel alarm outputs to short together
(alarm relay closed). Ratings for the alarm relay and network-controlled closures are 100 mA at
30 VDC.
The two contact closures are controlled via the COMPEL command stream from the uplink. See
the COMPEL™ Manual for the commands and structure for the relay closures.
In order to comply with the requirements of FCC Part 15 Subpart B, Class A emissions,
please read the following instructions on the protection of all output wiring and cabling:
For each monaural audio output (two per stereo channel), and for each alarm or user-
controlled relay output THAT IS USED, a single ferrite core must be used for EMI
emission suppression. The ferrite cores are supplied in the shipping container along with
the Unity4000 IRD. Details on assembly of the ferrite cores on the wiring are shown in
Figure 2-2. Note that each pair (or three, if the audio grounds are included) of wires must
pass through the core twice. Be sure that this is done as close to the removable screw-
terminal strip as possible. If minimal slack is used in the outer “turn,” the ferrite core
should be properly restrained by the wiring alone.
In addition to the above precautions for the wiring to the screw-terminal strips, the user is
cautioned to only use high-quality shielded cabling for the SERIAL 1, SERIAL 2, and
TRANSPORT OUTPUT connectors.