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Control head - front panel
The Front Panel PCB allows user control of the transceiver. An integral rubber keypad provides functional
control including speaker volume. The LCD display presents channel, frequency and status information.
Backlighting for the LCD and keys is provided. The microphone / speaker connector is captive and allows
the use of a three button speaker / microphone, providing PTT and channel Up/Down functions.
The front panel display is a 128x64 pixel, transflective LCD with LED backlighting. The display is
comprised of left and right banks which are written to via the microcontroller U5. The display uses 3
different fonts generated which are stored in the Flash Memory of the PIC. The ellipse and various images
are also stored there.
Another feature of the Front Panel is the Infrared capability. The infrared device D21 is located underneath
the “Enter” button on the front panel. When it detects a primary infrared device, all other processes and
button presses (except the power) are suspended. Using the Barrett Programming Software, data packs
can be uploaded or downloaded to the transceiver at a baud rate of19200. This process takes between 20
to 45 seconds.
The front panel communicates with the body of the transceiver using RS232 format this is provided by
RS232 transceiver U1.
Backlighting for the keys is provided by LED's. The LCD display has LED back lighting, the brightness of
which is controlled by a pulse width modulated signal for high efficiency. This signal is fed to MOSFET Q1
can be selected from the keyboard menu. See operator’s handbook for more details.
Microphone - Speaker
The microphone used with this series of transceivers is of the electret type and incorporates an inbuilt
loudspeaker. Provision is also provided on the rear panel for an external loudspeaker. Channel up / down
keys are also provided on the microphone
.