SoftHangup() — Performs a soft hangup of the requested channel
Hangs up the requested channel. The
options argument may contain the letter
a, which causes all channels on the
specified device to be hung up (currently, the
options argument may contain only a).
; hang up all calls using Zap/4 so we can use it
exten => 123,1,SoftHangup(Zap/4,a)
exten => 123,2,Wait(2)
exten => 123,3,Dial(Zap/4/5551212)