Back-to-back Automatic Callback activation for the same remote station must have an interval of 32 seconds. This limitation of 32 seconds interval applies only when Automatic Callback is invoked remotely over a SIP trunk. It does not apply when Automatic Callback is invoked by using QSIG or Distributed Communication System (DCS).

However, this limitation is not applicable to back-to-back Automatic Callback activation for an internal station.