4TK-81021. Controls and Functions1-1. Front Panelq (Power) switchPress to switch the transceiver ON. Press and hold forapproximately 1 seconds to switch the transceiver OFF.w s keyPress to increase the volume level.e t keyPress to decrease the volume level.r l keyPF (Programmable Function) key. The default setting ofthis key is None (no function). The programmable func-tions available for this key are listed below.t keyPF (Programmable Function) key. The default setting ofthis key is Monitor (page 5). Other programmable func-tions available for this key are listed below.y 1/ 2/ 3/ 4 keysPress to select a channel from 1 to 4.u Microphone jackInsert the microphone plug into this jack (the micro-phone is an optional accessory).i SpeakerInternal speaker.o PTT switchPress this switch, then speak into the microphone to calla station.1-3. Auxiliary Programmable Functions:• Emergency • Scan On/OFF• Key Lock • Talk Around• Monitor • Temporary Delete• None (no function)1-2. MicrophoneIndicator DescriptionLight while transmitting.Lights when a signal is detectedon the currently selected channel.Lights while the function pro-grammed onto its correspondingkey is activated.Lights while the function pro-grammed onto its correspondingkey is activated.Lights to display the currently se-lected channel (1~ 4)OPERATING FEATURES1-5. Rear panelExternalspeaker jackPower inputconnectorAntenna connector1-4. Displayq w e tryuio