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Support for Reliable DTMF Tone Signaling for WLL Applications. Submitted to TSG-C WG 1.1 by CDG-WLL Team Presented by James Warden and Julia Kwok Nov 17, 1999. Abstract.
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Support for Reliable DTMF Tone Signaling for WLL Applications Submitted to TSG-C WG 1.1 by CDG-WLL Team Presented by James Warden and Julia Kwok Nov 17, 1999
Abstract • The contribution provides a test plan to ensure reliable DTMF tone signaling with any vocoder (such as SMV, EVRC, etc. ) on the Forward Traffic Channel.
Background • The test plan for reliable DTMF signaling has been reviewed and supported by the CDG-WLL Team.
Recommendation • Have a requirement for all future Vocoder development that specifies that DTMF tones shall be passed reliably on the Forward Traffic Channel.
Problem Description Land Party MSC NIU Answering Machine Base Station
DTMF Signaling with EVRC • Issue: WLL peripheries require reliable receipt of DTMF Tone signals. • Problem: Some vocoders such as EVRC distort the DTMF tones to such a degree that they cannot be decoded at the other end.
DTMF Signaling with EVRC • Impact: the terminating end cannot be controlled reliably by DTMF tones passed through the EVRC vocoder on the Forward Traffic Channel. • Example: can leave a message but is not able to retrieve messages from an answering machine.
DTMF Signaling with Any Vocoder • Ensure reliable transportation of Forward DTMF tones over the air interface when any vocoder is used. • Developed Stage 2 and 3 Inter-operability Test Plan (added section 2.32.2).
Base Station Landline phone Answering Machine Network Interface Unit DTMF source (PC) Audio coupler Audio Coupler DAT Recorder DAT Recorder Land Party to Terminal CallReliable DTMF Tone signaling with a Vocoder for WLL Applications • Method of Measurement (section 2.32.2.2)
Land Party to Terminal CallReliable DTMF Tone signaling with any Vocoder for WLL Applications Minimum Standard (section 2.32.2.3) • Applicable to both Burst and Continuous DTMF. • Performance of the NIU peripheral (answering machine) based on rate of success and failure. • Burst DTMF: verify receipt of same digit. • Continuous DTMF: verify same digit, ON length and OFF length.
Minimum Standard • Frequency (section 2.32.2.3.1): same as reverse link standard. • Timing (section 2.32.2.3.2): • Recommended ON length DTMF pulse width (table 2.32.2.3.2-1). • Recommended minimum Inter-digit interval (table 2.32.2-2)
Conclusion • CDG Stage 2/3 tests to ensure reliable DTMF tone signaling with any vocoder on the Forward Traffic Channel. • Incorporate these tests into any other SMV Interoperability Test documents.