H04Q1/444 - CPC Classification Index

ClassID:

231185 ⎘

H04Q1/444 - 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

Sub-classes:

H04Q1/446 » using one signalling frequency 0
H04Q1/45 » using multi-frequency signalling 54
H04Q1/46 » comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency, e.g. speech current 18

Recent Application in this class:

20090240826

2009-09-24

Using RTCP statistics for media system control

20050180529

2005-08-18

Signal detector