These are multi-channel FRS / GMRS radios. In order to receive transmitted signals from the other radio, they both must be set to the same Channel and the same Interference Eliminator Code. One without the other will keep audio from being heard on the receiving radio.
I suspect you need to refresh yourself with the radio's controls and settings. If you have lost the manual, you can get a copy free of charge from
Motorola You'll need a free program called
Adobe Reader to view it.
Once you have everything - look at the right hand side of page 1 for "Talking and Listening" followed by "Menu Options" to set the radios up correctly. Keep in mind that if VOX is selected, and there is sound near both radios, they both will transmit at the same time - since the radios receive OR transmit at any given time, no audio will be heard from either.
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