We recently purchased the Motorola MS350 radios with headsets. We plugged the headsets in and turned the power on, but are unable to communicate back and forth in handsfree mode. We can switch to PTT and it works fine, but we really would like to use them in VOX mode. Any ideas? Thank you in advance.

Various help in the links, and the first site woulf be a good place to ask

https://forums.lenovo.com/t5/Stereo-Bluetooth-Headsets/T605-Pinout-for-UIM-Plug/m-p/2461493?page=1

https://manualsdump.com/en/manuals/motorola-t605/221217/5

https://www.google.com/search?q=Motorola+t605+power+plug+pinout&rlz=1C1QJDB_enCA643CA644&sxsrf=ALiCzsbv1-Hiez91Xp_6VDZLInXCJc6h7w:1651431433109&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjm08O__b73AhXRPM0KHTgyBxkQ_AUoAXoECAEQAw&biw=1920&bih=937&dpr=1

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If your frequency and code are set the same, you have either a battery problem or a radio problem. For a quick battery test, swap the battery pack from the good radio into the one with the problem and see if the problem moves. Then you will know if it is simply the battery. If both settings are identical and the battery swap does not solve the problem, you have a defective radio.

A few things come to mind: 1) Be certain your radio is turned off when plugging in an audio device. This insures they are pairing properly. 2) Be certain the audio device is plugged in all the way to the click position. You should feel a slight click when it is seated properly. 3) If the jack on this radio is slightly wobbled out from audio devices being plugged and unplugged the headset's plug may not be touching the sweet spot to make transmitting possible. Press slightly to the side on the plug's grommet to see if it works. If this is the case, trade headsets with another unit and see if you still have the same problem. Sometimes it is as simple as playing musical chairs with audio devices. 4) If you are using the radio in digital mode, not all audio devices will work. Check with your Motorola dealer to see which audio accessories will work with your unit in digital mode. (They will have a digital emblem stamped on them.)

Likely a bad battery. Most radios will flash red when a bad battery is in them.

This is likely because your radio's battery has lost enough power that it cannot fully power the headset and the radio both. Or there is a component in the headset or radio which is getting overheated and will not function properly. Try the headset on another radio at the time of failure and see if it is still in failure mode on the other radio. Or try changing the battery to a fully charged battery and see if the headset then functions correctly. These test will help you determine which component is failing.

check your radios settings, this should be available in a menu on the radio... the user manual does not show a setting for non vox operation of the head set, (as this maybe a version difference it may be available in the menu) so if it is not available in the menu with the rest of the settings it is not an option.

The three things which come to mind are:
1) Is the headset the VOX headset intended for the radio model? Sometimes the rings on the plug do not match the internal points of contact if it is not the intended headset. Not all headsets are VOX capable.
2) Is the headset plugged in all the way. (You mentioned plugging in and then turning on. This is good. You must always have the radio turned off when plugging or unplugging an audio device.)
3) Try pressing the PTT on the headset cord one time before switching the dip switch to VOX. (Assuming you have a headset with the small box in the line.)

Check your VOX/ iVOX settings. You will need VOX for using an audio device.

Lastly, if you continue to have difficulties, contact Motorola at the 800# provided in the user guide. They should be able to assist you.

Best regards.

Check your programming. The radio may simply be on a different frequency and/or interference eliminator code than the other units. Also check your audio jack to be certain nothing is plugged or stuck in the jack. The radio is sensitive to a device being plugged in the jack, and when something is plugged in, it turns off the speaker to the radio.

Best regards.

Likely not compatible. One thing to try is to make certain the transmitting unit is turned OFF when you initially plug in the headset. Sometimes if a headset is plugged into a radio when it is already ON, the headset will appear to be in VOX (voice activated) mode and will not allow the user to receive. Also, if this headset has an inline PTT, it may not be compatible with the radio and you would need to use the PTT on the radio.

If this doesn't work, you would need to use the TalkAbout headset designed for the MR350.

Best regards.

Is the headset in the discover mode? Usually its a 2 button press and hold until the led blinks or changes color.