PRI dial with billing

; Set the account code to 'benshaw' if there is no account code given as ARG2.  Then dial out the PRI[macro-pri-dial]exten => s,1,SetVar(ACCOUNTCODE=${ARG2})exten => s,n,GotoIf($[{$ARG2} != ""],n+2)exten => s,n,SetVar(ACCOUNTCODE="benshaw")exten => s,n,SetAccount(${ACCOUNTCODE})exten => s,n,Dial(${BELLTRUNK}/${ARG1})exten => s,n,Wait(5)exten => s,n,Congestionexten => s,n+100,Busy