8
Uninstalling the Radio
11 Four Way Navigation Key
Press up, down, left or right for list scrolling, while moving 
around the menu hierarchy, or for alphanumeric text 
editing.
12 Programmable External Alarm Key
Default function: Used to activate and deactivate the 
External Alarm (Horn & Lights).
13 Programmable Speaker Control Key
Default function: Switch speaker On/Off.
14 Programmable Backlight Key
Used to dim or intensify the radio’s backlight. It has five 
intensity options.
15 Push-To-Talk Button (PTT)
Press and hold this side button to talk in Simplex calls or 
to initiate a group call, release it to listen.
Press to send status and text messages.
16 Microphone
Before using your MTM800E for the first time, remove the plastic 
lens protector from the display.
It is recommended to turn off the terminal before connecting any of 
the accessories.
OPTION 1:
Before disconnecting the 13.2V main power supply 
from the radio:
1. Switch off the radio.
2. Wait for a minimum of 4 seconds after the radio 
Off Switch is released.
Disconnect the 13.2V main power supply.
OPTION 2:
Turn off the main power supply WITHOUT 
switching OFF the radio.
Item Description