[Freeswitch-users] Short word drop-outs

Got a customer who's complaining that short words are being lost in conversations over VOIP/Freeswitch. I presume this is over-enthusiastic silence suppression which could be tweaked in the freeswitch config. I wondered if this might be a handset config issue, but they claim that they can use their handsets with other VOIP providers that don't show the same problem. Any tips?