18M ONITORPress the key programmed as Monitor to turn the transceiver signalling OFF.While signalling is OFF, you can hear all signals received on your currentchannel. With signalling ON, you can hear only signals that match the signallingprogrammed in your transceiver. Press the Monitor key again to return tonormal operation.Press and hold the key programmed as Monitor for approximately 1 second tolisten to weak signals that you cannot hear during normal operation, and toadjust the volume when no signals are present on your selected channel. Pressthe Monitor key again to return to normal operation.• The icon appears on the display while Monitor is activated.OPERATOR SELECTABLE T ONE (OST)You can change the preset encode and decode tones for the selected channel.Upt to 12 tones can be pre-programmed by your dealer.1 Press the key programmed as OST.• “ ” or the OST number appears on the display.2 Press the CH / keys (right side) to select the desired OST.To exit OST mode and return to the preset encode and decode tones, press theOST key again.KEY L OCKPress the key programmed as Key Lock to lock the keys of the transceiver.Locking the transceiver keys prevents you from accidentally changing thechannel and channel settings. While key lock is active, you can still use themicrophone PTT switch, the (power) switch, and the Emergency and Monitorkeys. If set up by your dealer, you can also use the Volume keys.• The icon appears on the display while the Key Lock function is ON.Press the Key Lock key again to turn this function OFF.HORN A LERTHorn Alert is a useful feature that will notify you of a received call while you areaway from your vehicle. The transceiver is programmed to sound the vehiclehorn or some other external alert device (such as the vehicle headlights) when acall is received that has correct signalling.Toggle Horn Alert ON and OFF by pressing the key programmed as Horn Alert.• “ ” appears on the display while Horn Alert is turned ON.