Retevis RT638 Operating Instructions Manual page 6

TOT
Time out timer means the unit will automatically stop transmit after 30sec or 60 sec continuously transmit. Press
Menu button 5 times,
screen will display 60 TO, and then press Up or Down button can choose 60 or 30 seconds or OFF. Default
setting is 60 seconds, and press the PTT button to confirm changes.
Roger Beep
Roger beep means a tone added to the end of broadcast. It indicates that the user/operator has concluded
speaking.
This is a tone which is automatically transmitted whenever the PTT button is released. This alerts the receiving
party that you have ended the transmission, and you are now in receive mode. Press Menu button 6 times,screen
will display ON RO, then press Up or down button to choose RO OFF or ON. Press the PTT button to confirm
changes.
Key tone
Symbol will be on the display when Key tone is opened.
Press Menu button 7 times, screen will display Bell ON, and press Up /Scan button to choose ON or Down/MONI
button to choose OFF.
Default setting is ON, press the PTT button to confirm changes.
DCM
Dual channel monitoring you can monitor between two channels eg: 1 to 8 or 9 to 22. Press Menu button 8 times,
screen will display DCM OF, and press Down or UP button to choose DCM OFF or ON. When choose DCM is on,
press Menu/PWR button one time, then scroll Up/Down button to choose channel. The channel can not be the
same as main channel. Press the PTT button to confirm changes.
Transmitting (sending speech)
The unit is continuously in the Receive mode when the unit is turned ON and not transmitting.
When a signal is received on the current channel, "RX" icon will be displayed on the LCD screen.
a. Press and hold the PTT (Push to Talk) button to transmit your voice. The transmit signal icon "TX" will display
on the LCD screen.
b. Hold the unit in a vertical position with the Mic (Microphone) 5cm away from the mouth. While holding the PTT
button, speak into the microphone in a normal tone of voice.
c. Release the PTT button when you have finished transmitting. For others to receive your transmission, they
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