gate1*CLI> show channels
        Channel  (Context    Extension    Pri )   State Appl.         Data
0 active channel(s)
    -- Accepting call from '154' to '5540' on channel 0/7, span 1
    -- Executing SetCDRUserField("Zap/7-1", "machine=gate1") in new stack
    -- Executing Dial("Zap/7-1", "Zap/G3/5540") in new stack
Jan  7 11:47:50 WARNING[10304]: chan_zap.c:4500 zt_new: Channel 71 already has a Real call
Jan  7 11:47:50 NOTICE[10304]: app_dial.c:828 dial_exec: Unable to create channel of type 'Zap' (cause 0)
  == Everyone is busy/congested at this time (1:0/0/1)
    -- Channel 0/7, span 1 got hangup
    -- Hungup 'Zap/7-1'
gate1*CLI> show channels
        Channel  (Context    Extension    Pri )   State Appl.         Data
0 active channel(s)