SIP/fred is the secretary's phone
And this is the context for my zap channels

[incoming]

exten => s,1,Answer
exten => s,2,NoOp(Incoming call from "${CALLERID(name)}" <${CALLERD(num)}> on channel $CHANNEL})
exten => s,3,Dial(SIP/fred,12,t)
exten => s,4,Voicemail(u104@default)
exten => s,5,Hangup

exten => a,1,VoiceMailMain(104@default)