Off-network Call Coverage

Last Updated : Oct 30, 2012 |
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You can use standard remote coverage to an external number to send a call to an external telephone. However, the system does not monitor the call once the call leaves your system. Therefore, if the call is busy or not answered at the external number, the call cannot be directed back to the system.
Note:
Using remote coverage, you cannot cover calls to a remote voice mail.
Using the Coverage of Calls Redirected Off Net (CCRON) capability, you can use an external number in a coverage path. The system monitors the call to determine whether the external number is busy or unanswered. If necessary, the system can redirect a call to coverage points that follow the external number. Any coverage point can be an off-network destination.
Use this capability for a call to follow a coverage path that:
  1. Starts at the called extension
  2. Redirects to the home telephone, and if unanswered at home
  3. Returns to the voice mail box of the called extension
Note that the call does not return to the system if the external number is the last point in the coverage path, except when no trunks are available to route the call. In that case, the system attempts to again terminate the call at the original called extension.
When the system redirects an incoming trunk call off the network, a timer is set. The timer prevents the system from redirecting other incoming trunk calls from redirecting off the network until the timer either expires or is cancelled. The timer prevents calls that were redirected off the network from being routed back to the original telephone number from the off-network destination. Calls that are routed back to the original telephone number in this situation effectively create a loop that seizes trunks until trunks are no longer available.
The system provides the means to perform call classification on an off-network coverage call to determine the disposition of the call. If the off-network call is carried completely over ISDN facilities to the final destination, ISDN trunk signaling is used to monitor the call. If ISDN trunk signaling is not used to monitor the call, a call classifier port is used to cancel the call.
When the system tries to use a call classifier port to classify an off-network coverage call, the system introduces an unavoidable cut-through delay while the call classifier port attempts to identify an answered call. Neither the originating party nor the answering party hears each other during the 1-second or less delay. A call classifier is attached to all off-network coverage calls, that are made over analog facilities or over ISDN facilities, if the call is interworked to non-ISDN facilities on the public network.
When you enable CCRON:
  • The system monitors off-network calls and returns the calls to the system if the calls are not answered within the administered time interval. Calls also return to the system if the system detects a call progress tone, such as busy or reorder.
  • A simulated bridge appearance (SBA) is put on the called extension, and the green lamp flashes. A user can answer the call at the called extension at any time.
  • When the system uses a call classifier port to classify the call, the system plays local ringback tone to the caller while the system is classifying the off-network call. The system uses the local ringback tone so that the user does not hear what is happening on the public network. As a result, the calling party will not hear the first few syllables that the answering party speaks.
  • If any party on the call is on hold when the system routes the call off the network, the call classifier is removed from the call. The call behaves as if CCRON is not enabled.
  • While an off-network call is undergoing call classification, any party that is not already on the call cannot bridge onto the call. Also, the originating party cannot release the call, conference anyone else onto the call, or transfer the call to a new party. Once the call is answered at an off-network destination, or the call is returned to the system for further call processing, these restrictions are removed.
  • If the last point in a coverage path is an off-network destination and no trunks are available to route the call, the system attempts to again terminate the call to the called extension.
  • The system has no control over any redirection of the call that might take place at an off-network destination. However, further coverage treatment is provided if the off-network redirection interval expires before the call is answered at an off-network destination.