Memorex MK1995 - Manual (Page 25)

Operation
22
LCD Back-Lighting Lamp
This lamp is used to illuminate the LCD screen. It turns on every
time you press and release the monitor (MON)button momentarily.
The lamp will go out after 4 seconds.
TX / RX Indicator LED Lamp
When the PTT button is pressed, the red (TX) LED will light to
confirm transmitting signal. When you are receiving signals from
another party, the green (RX) LED will light.
Auto Power Saver
Your MK1995 unit has a unique circuit designed to extend battery
life. If there are no transmissions within 5 seconds, the unit will
automatically switch to Battery Save Mode.
TX/RX LED
indicator