[dialout9999]
exten => s,1,Read(callto,dialtonez0r,21)
exten => s,2,SetVar(CALLFILENAME=${callto:1}-${TIMESTAMP})
exten => s,3,Monitor(wav,${CALLFILENAME},m)
exten => s,4,Dial(SIP/${callto}@bv,45,Hg)
exten => s,5,goto(s|1)