PBX Call Setup Delay Elimination via Voicemail Redirection
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Solution Overview
Problem
Mobile devices are often unavailable or out of range, leading to delays in establishing voice calls with PBX systems due to the need for confirmation tones, which introduce a 2-second delay before users can begin talking.
Innovation Solution
Reprogramming the voicemail number to a Direct Inward Dial (DID) number that can be monitored by the PBX, allowing it to infer call success without waiting for confirmation tones, thus eliminating the delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If confirmation tones are sent and processed to verify mobile device availability, then call connection reliability is improved, but call setup time increases by 2 seconds
Solution Approach 1:
The system performs preliminary actions by having the mobile device send its availability status (via voicemail number provisioning) to the network before the actual call is initiated. This allows the PBX to already know whether the mobile device is available when the call is made, eliminating the need for confirmation tones during call setup and reducing call setup time while maintaining reliability
2Measurement precision
If confirmation tones are used to detect mobile device availability, then accurate availability detection is achieved, but user experience deteriorates due to delayed conversation start
Solution Approach 1:
The mobile device's availability status is determined in advance through voicemail number provisioning and stored in the network before the call is initiated. This preliminary determination of availability eliminates the need for confirmation tones during the call, providing both accurate availability detection and immediate conversation start for improved user experience
3Loss of time
If voicemail number is reprogrammed to DID number for monitoring, then call setup time is reduced, but system complexity increases
Solution Approach 1:
The voicemail number is given multiple functions: it serves both as the traditional voicemail access number and as a monitoring mechanism for mobile device availability. By provisioning the mobile device's voicemail number with availability status information, the system uses an existing number for dual purposes, reducing call setup time without adding significant system complexity
Solution Approach 2:
The mobile device itself provides the availability information by having its voicemail number provisioned with status data. The device essentially monitors and reports its own availability state through the network, eliminating the need for separate monitoring mechanisms and reducing overall system complexity while achieving faster call setup
Data Source
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AI summary
Aspects relate to initiating voice calls to mobile devices from an enterprise network. In one example, a server can initiate a voice channel to a mobile device, and if the mobile device cannot be reached, an access network may redirect the call from the server to a number identified as a voicemail number; however, such number is reconfigured to instead be directed to a number located within the enterprise network. The server can monitor or receive an indication that a call is incoming, and attributable to the mobile device. If such a call is incoming or received, then the server determines that the call has failed. If the mobile device answers the call, the server can determine that the voice channel has been established, without waiting for a confirmation indication, such as a DTMF tone.