H04Q1/44 - CPC Classification Index

ClassID:

231181 ⎘

H04Q1/44 - CPC Classification

Classification description:

Details of selecting apparatus or arrangements; Electrical details; Signalling arrangements; Manipulation of signalling currents using alternate current

Sub-classes:

H04Q1/442 » with out-of-voice band signalling frequencies 0
H04Q1/444 » with voice-band signalling frequencies 2

Recent Application in this class:

20070291928

2007-12-20

Tone, modulated tone, and saturated tone detection in a voice activity detection device

20070263842

2007-11-15

Enhanced tone detector including adaptive multi-bandpass filter for tone detection and enhancement

20050185782

2005-08-25

Local control of call features in a telephone system

20050047586

2005-03-03

Tone, modulated tone, and saturated tone detection in a voice activity detection device