HI, all I'm sure the usb dongle is unlocked and support voice feature ( AT+CVOICE GOT 0) . The problem is , usb dongle can make call ,but both side of the call can not hear the voice . I'm almost give up . Any advise will be appreciate. Raymond Hi all, I'm using GSMOpen module with freeswitch master version (pulled from git). The usb dongle for test is Huawei E173 , hardware info checked by dc-unlocker is : Found modem : E173 Model : Huawei E173 IMEI : 860872014****** Serial NR. : ADABYA9340****** Firmware : 11.126.25.00.76 Compile date / time : Mar 27 2012 15:57:50 Hardware ver. : CD1E153M Dashboard version : UTPS23.009.09.00.76_MAC23.009.09.00.76 Chipset : Qualcomm MSM6290 Voice feature : enabled SIM Lock status : unlocked Wrong codes entered : 0 (unlock attempts left : 10) I've make test 2 ways. Test A: Using another phone call-in Freeswitch ,with IVR module , caller will hear the ivr voice , dtmf function worked well ,but record file have only called party voice ( ivr voice), caller have no voice record (i'm sure the dialplan record function workwell when NOT using gsmopen module). Test B: Freeswitch+gsmopen as call out. I'm using MicroSIP softphone make a sip call ,and gsmopen as b-leg to deliver the call. ( <actionapplication="bridge" data="gsmopen/ANY/${destination}"/> ) I tried TestB several times , the best result , called party hear the caller voice , but caller cann't hear called party voice always. So ,Any advice to resolve the problem will be appreciate. Raymond