FTA-750/FTA-550 O perATing MAnuAl20B asIc operatIonTransmission (COM Band) To transmit, press andhold the PTT switch.Speak into the micro-phone area of the frontpanel grille in a normalvoice level.The “TX” icon, whichindicates that the FTA-750/FTA-550 are inthe transmit mode, ap-pears on the display.PTTSQL127.300VOLTX To return to the receive mode, release the PTTswitch.Operating Advice: Use of Internal MicrophoneYour FTA-750/FTA-550 are extensively sealed against water ingress, so as to ensurereliable operation even if it has become submerged. This unique construction includeswaterproofing seals around the microphone and speaker enclosure, requiring that care beexercised when speaking into the internal microphone.Please refer to the illustration, and observe the location of the internal microphone. It isimportant that you focus your speech in the direction of the microphone’s location, so asto ensure sufficient voice input to the radio.If you find it difficult to utilize the FTA-750/FTA-550 conveniently and safe whilespeaking directly into the microphone, we recommend the use of the SSM-10A Speaker/Microphone (option), or an after-market aviation headset/boom microphone.