Tait TM8000 Series, Service Manual

Page: 23 / 244

TM8100 Mobile Radio Service Manual Introduction 23
May 2004 © Tait Electronics Limited
1.3 Control Head
Introduction
The control head clips securely to the front of the radio body. The
control-head loom between the two is enclosed in the space between
them. For badging and branding purposes there are both a logo and a
label for the product model code on the front panel. The control head
may also be left unbadged. For the control heads with UI, the essential
features are shown in the block diagram of
Figure 1.6 .
Control Heads with UI
The front panel of the control heads with UI is fitted with the controls
and indicators needed by the radio user; these comprise:
■
LCD (liquid-crystal display) screen
■
indicator LEDs (light-emitting diodes)
■
volume control
■
ON
/
OFF
key
■
function keys
■
channel-selection keys
In addition, there are the microphone connector and an internal speaker.
The necessary circuitry for the above items is mounted on a control-head
board fitted behind the front panel. The volume-control potentiometer
is fixed to the board; so is a control-head connector, which is used for
the control-head loom between the control head and radio body.
Options for Control
Heads with UI
The control heads with UI allow for an optional concealed microphone
or the use of a dynamic microphone. (A concealed microphone is fitted
behind the front panel next to the speaker.) With either option a separate
circuit board is required for the microphone. This board is connected to
the control-head board by means of two connectors; the plugs of the
connectors are mounted on the latter board and the sockets on the
former. Full details of the optional microphones and circuit board are
given in the accessories manual.
Blank Control Head
The blank control head has none of the features of the control heads with
UI. The front panel of the blank control head is fitted only with the
single programming connector. The control-head loom is permanently
fixed to the rear of the programming connector. The space inside the
control head can be used for the fitting of an optional third-party circuit
board, but is otherwise empty.