Parts List

Table Of Contents
2-8
Transmitter Main Board Instruction Manual
2.2 MT-3 Front Panel Board
The MT-3 Front Panel Board is a subsection of the MT-3
Transmitter
Board
which
is used to
mount the front panel
switch,
diode,
and
microphone
connector.
The main purpose of the board is
to
eliminate
a
wiring
harness for the front panel components. Jumper J1,
located
on the rear of the
circuitboard,
is used to
select
whether
or not the MIC PTT line
activates
the
transmitter's
TOT.
Jumper J2 is used to
select
whether
or not Rx Audio or 13.8
Volt
is supplied to pin 4 of the
microphone.
Jumper J1: 'x' position MIC PTT NTO no
time-out-timer
(factory setting)
'y' position MIC PTT WTO
with
time-out-timer
Jumper J2: 'x' position Rx Audio
enabled
to MIC-4 pin (factory setting)
'y' position
+13.8
Volts
supplied to MIC-4 pin
Refer to section 5.3.2 "MT-3 Front Panel Board
Schematic
Diagram".
2.3 MT-3 Audio Processor (Version 1.6)
invisible
text
2.3.1
General
The MT-3 Audio Processor is a
versatile
circuitboard
that can
provide
several
types of audio
processing for
voice
or data transmission. Two analog
switches
on the audio processor, co
ntrolled
by a common
signal,
make it possible to
transmit
voice
or data. A continuous
+9.5
Vdc supply
and a
switched
+8.0
Vdc supply are required to power the module. The MT-3 Audio Processor is
backwards
compatible
to Daniels
Electronics
MT-2 series tr
ansmitters.
Refer to section 5.4.1
"MT-3 Audio Processor
Component
Layout" and to section 5.4.2 "MT-3 Audio Processor
Schematic
Diagram" for
component
location
and
designation
references.
2.3.2
Power Requirements
The audio processor can be configured for continuous audio standby or for
switched
audio standby
by the
Transmitter
Main Board. If fast audio
risetime
is
desired,
the
transmitter
should be
operated
in standby mode 2 or 3 as
specified
in section 2.1.2.7. Power for the
microphone
input and the
balanced
input can be
separately
disabled by jumpers J3 and J4
respectively
if the input is not
required. This results in a current savings of
approximately
11 mA per input. The current
requirements
for the MT-3 Audio Processor are shown in
Table
2-1. The current for the
associated
TOT is
approximately
4 mA when the
transmitter
is keyed and is
included
in the keyed
values
in the
table
below.