H04Q1/453 - CPC Classification Index

ClassID:

231190 ⎘

H04Q1/453 - CPC Classification

Classification description:

Details of selecting apparatus or arrangements; Electrical details; Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling in which m-out-of-n signalling frequencies are transmitted

Recent Application in this class:

20160337524

Robust DTMF detection in an unreliable voice-over-IP (VoIP) environment

20140169550

Robust DTMF detection in an unreliable voice-over-IP (VoIP) environment

20110200147

High-performance tone detection using a digital signal processor (DSP) having multiple arithmetic logic units (ALUs)

20110013766

METHOD AND APPARATUS HAVING ECHO CANCELLATION AND TONE DETECTION FOR A VOICE/TONE COMPOSITE SIGNAL

20070116242

Method and apparatus for decoding DTMF tones

14011813

Recovery of DTMF tones in the presence of periodic interference and obstruction