Ken, are they Kenwood Funkey radios by any chance? I use them with a Pro7 Sport and they are fine if set up properly:
I found that by entering the setup menu on the radios and increasing the VOX sensitivity, and adding more time to the post-talk transmit function, they work much better. Also, try not to have the volume knob on the radios set to more than 80% otherwise you may experience 'clipping' of the Autocom amplifier ('Norman Collier' style conversations).
I have the VOX adjuster on the autocom unit set to about the 90 MPH position to prevent random cutting in from wind noise. A simple blow across the mic before starting to speak opens the channel on VOX and keys the radio into transmitting.
If you are talking to someone using a TK3101 Kenwood radio, you need to set your channel and sub-group on the Funkey (and TK3101) in accordance with the chart in the Funkey handbook as they don't use exactly the same settings, hence you may be able to recieve but not transmit, or vice-versa, or suffer headaches trying to get it to work until you follow the compatibility chart:
TK3101 / FUNKEY
Ch 1 / Ch 1, Gp Mode 10
Ch 6 / Ch 2, Gp Mode 18
Ch 3 / Ch 3, Gp Mode 13
Ch 5 / Ch 4, Gp Mode 17
Ch 8 / Ch 5, Gp Mode 7
Ch 12 / Ch 6, Gp Mode 6
Ch 7 / Ch 7, Gp Mode 19
Ch 10 / Ch 8, Gp Mode 15