Patent classifications
H
ELECTRICITY
Load children
H04
ELECTRIC COMMUNICATION TECHNIQUE
Load children
H04Q
SELECTING
Load children
1/00
Details of selecting apparatus or arrangements
Load children Filter patents View analytics View as hierarchy
H04Q1/30
Signalling arrangements; Manipulation of signalling currents
Load children Filter patents View analytics View as hierarchy
H04Q1/32
using trains of DC pulses
Load children Filter patents View analytics View as hierarchy