[Apr 23 10:17:21] WARNING[3036]: chan_zap.c:1625 zt_set_hook: zt hook failed: Device or resource busy
    -- Starting simple switch on 'Zap/1-1'
    -- Hungup 'Zap/1-1'
[Apr 23 10:17:23] WARNING[3036]: chan_zap.c:1625 zt_set_hook: zt hook failed: Device or resource busy
    -- Starting simple switch on 'Zap/1-1'
    -- Hungup 'Zap/1-1'
[Apr 23 10:17:26] WARNING[3036]: chan_zap.c:1625 zt_set_hook: zt hook failed: Device or resource busy

zap show channels
   Chan Extension  Context         Language   MOH Interpret
 pseudo            from-pstn                  default
      1            from-pstn                  default
      2            from-pstn                  default
      3            from-pstn                  default
      4            from-pstn                  default
      5            from-pstn                  default
      6            from-pstn                  default
      7            from-pstn                  default
      8            from-pstn                  default
*CLI> zap show status
Description                              Alarms     IRQ        bpviol     CRC4 
wrtdm Board 1                            OK         0          0          0