TM9300/TM9400 Installation Guide
Installing the Radio
31
© Tait Limited
December 2015
Power Connector
The power connector is the interface to the vehicle battery and an optional
external remote speaker. Connecting a remote speaker is described in
“Connecting an External Speaker” on page 33
.
Notice
This radio is designed to operate from a nominal 12V nega-
tive ground supply and may draw up to 15A of current. The radio will
tolerate a supply voltage range of 10.8V to 16.0V at the radio.
Selecting the Power
Source
In passenger vehicles, the radio is always connected directly to the battery
using the power cable provided.
Notice
Do not connect the radio to the centre tap of two 12V batter-
ies! This may result in damage to the radio due to earth loops, in partic-
ular when the negative lead is disconnected from the vehicle battery. It
may also result in overcharging or undercharging of the batteries, reduc-
ing their service life.
In trucks, where direct connection to the battery is often not possible, the
radio can be connected to a suitable terminal inside the fuse box that is
connected directly to the battery.
24V-to-12V
Converter
In vehicles with a supply voltage larger than 16.0V, such as many trucks, it
is essential to provide a 24V-to-12V converter with a minimum rating of
15A for radios 30-50W and 10A for the 25W radio. This will isolate the
radio from excessive battery voltage and provide the correct DC operating
conditions. Note that most 24V-to-12V converters already fitted are not
rated sufficiently.
Ignition Signal and
Standby Current
When connecting the radio to the battery without using the ignition signal
as described
, the standby current is approximately 50mA.
When using the ignition signal to turn off the radio, the standby current is
reduced to <3mA.
25W
Table 4.1
Power connector (radio) - pins and signals
Pinout
Pin
Signal name
Description
Signal type
1
AGND
Earth return for radio body power
source
Ground
2
SPK–
External speaker output.
Balanced load configuration
Analog
3
SPK+
External speaker output.
Balanced load configuration
Analog
4
13V8 BATT
DC power input for radio body and
control head
Power
1
2
3
4
rear view
25W radio
rear view
30-50W radio
25W