Guardian Telecom Inc.
Installation & Operation
TBA Models
1.
Purpose
This document is provided to assist in the electrical installation and operation of a Talk Back Amplifier
(TBA) as produced by Guardian Telecom Inc.
2.
Scope
The installation information will consist of connections to the TBA unit in the enclosure. The
connections to external speakers and microphones are covered in their respective manuals.
The operation information will consist of adjustment of potentiometers and power supply requirements
for the TBA unit.
Some information for the speaker and microphone sensitivity that relates to the TBA operation will be
given to assist in the selection and installation of TBA peripherals.
3.
Identification of equipment
There are several models of Guardian Talk Back Amplifiers (TBA). The Printed Wiring Board Assembly
(PWBA) in the TBA will support up to five speaker outputs; therefore the listing of equipment goes from
five speaker outputs to two speaker outputs.
3.1. TBA Model Numbering
The table below uses “CEN” for Central Station, “MON” for Monitored Station and #1 to #3 for
Stations #1 to #3. The “X” in a square indicates that the speaker amplifier is populated on the
PWBA. The “L” indicates low impedance and the “H” indicates high impedance.
Figure 1 - Table of TBA Models
Note:
The Central Station input for the microphone on TBA-33 is modified to have an impedance of
near 1K Ohm when the PTT is not pressed. See the section titled “Microphone” for further information.
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