PBX Call Setup Delay Reduction via Voicemail Reprogramming

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Solution Overview

Problem

Mobile devices experience delays when establishing voice calls with PBX systems due to the need for confirmation that the call was not redirected to voicemail, which results in a user waiting before being able to 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 whether the call was answered or redirected, thus eliminating the need for DTMF tone confirmation and reducing call setup time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the PBX waits for DTMF tone confirmation from the mobile device to verify call answer status, then call reliability is improved, but call setup time increases

Engineering Contradiction:

Improvecall answer verificationVSAvoidcall setup delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary configuration by reprogramming the voicemail number to a DID number that the PBX can monitor. This preparatory action enables the PBX to proactively detect call answer status through incoming call monitoring rather than waiting for DTMF confirmation, thereby reducing call setup delay while maintaining verification reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The DID number acts as an intermediary mechanism between the PBX and mobile device. Instead of directly receiving DTMF tones from the mobile device, the PBX monitors for incoming calls to the DID number, which serves as an indirect but more efficient signal that the mobile device has answered the call, thus eliminating the need for time-consuming DTMF exchange

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the system uses traditional voicemail number for call redirection, then call routing functionality is maintained, but call setup delay occurs due to DTMF tone processing

Engineering Contradiction:

Improvecall routingVSAvoidcall setup time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The system changes the parameter of the voicemail number by reprogramming it to a DID number. This parameter change transforms the number's function from a passive voicemail access point to an active monitoring target that the PBX can use to detect call answer status, thereby eliminating DTMF tone processing delays while preserving call routing functionality

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8615222B2System and method to detect PBX-mobility call failure

Publication Date: 2013.12.24 MALIKIE INNOVATIONS LTD

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.