US PATENT SUBCLASS 455 / 228
.~.~ Responsive to specified modulation (e.g., call alarm, Conelrad)

Current as of: June, 1999
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455 /   HD   TELECOMMUNICATIONS

130  DF  RECEIVER OR ANALOG MODULATED SIGNAL FREQUENCY CONVERTER {24}
227  DF  .~ Responsive to an input signal of particular predetermined frequency {2}
228.~.~ Responsive to specified modulation (e.g., call alarm, Conelrad)

DEFINITION

Classification: 455/228

Responsive to specified modulation (e.g., call alarm, conelrad):

(under subclass 227) Subject matter including means for indicating a predetermined modulation in the carrier.

(1) Note. Systems with a two-state indicator such as an alarm light off or on or with a filter passbanding a warning tone, are classified here only if combined with an analog carrier wave communication receiver.

(2) Note. Selective systems responsive to a predetermined signal(s) are classified in Class 340, subclasses 147+.

SEE OR SEARCH CLASS

340, Communications: Electrical,

539, for an alarm systems with a radio link.

343, Communications: Radio Wave Antennas, 100+, for directive receivers.