[App_rpt-users] Cell Phone audio to loud on IAX connection

Can some one give me a hint of how to deal with incoming cell phone audio that overdrives remote Allstar IAX connections. I have a couple friends that use their cell phone with (Android-IAX app) to connect to my nodes when no RF access is available. Incoming phone audio via IAX is way strong coming from that source. Yet other Asterisk/Allstar connections are just fine with the simple tune setting used. Being fairly new to the cell phone world (about 6 months) I still have no clue (and neither do they) as to how to manipulate mic volume on a cell phone or even if you can. Anyone have any hints on how they handle this problem? Larry - N7FM