Navicom RT-420 - 9 -Special function operationTX Time OutThe transmission will be automatically turn off after PTT key pressed over 5 consecutive minutes.The Tx mode will be terminate and back to Rx mode. Once the PTT key is released, the TX time outtimer will be reset. PTT key will work back normally.TX IndicatorWhen the radio is transmitting, the “TX” icon will be lit upEuropean key operationMost of the functions in the radio are the same as the US model. These are the functions that workdifferently.