Here are some of the most common FAQs on LAT-P20
Do all of the buttons light up?
The inside PCB board only has two 2 led's (LED 1 and LED 2) to light up the buttons. Numbers 3, 6, 7, * are far away from the light hence they don't light up as much as the ones closer to the LED's. This phone runs on very low power in order to keep the EMF levels low, so with more LED's added more power would be needed and this will also increase the EMF levels.