US PATENT SUBCLASS 178 / 49
.~ Superposed current
Current as of: June, 1999
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DEFINITION
Classification: 178/49
(under subclass 2) Composite systems and combinations of two or more distinct systems of transmission, usually by employing currents of different character for signaling, though not limited thereto. The superposed currents are generally produced by induction upon a line already carrying ordinary Morse or make and break current.
SEE OR SEARCH THIS CLASS, SUBCLASS:
44+, for wave transmitting systems having means to diminish or prevent distortion or attenuation, and especially applicable to long lines, cables, and systems having large capacity or inductance.
47, for simultaneous transmission of messages by harmonic or tone telegraphy.
51, for resonant circuits tuned by inductance or capacity, or both, to receive currents of particular frequencies.
SEE OR SEARCH CLASS 336, Inductor Devices, appropriate subclasses for the structure of transformers and inductive reactors.
370, Multiplex Communications, appropriate subclasses, particularly
496, 527, and 529 wherein a signaling or nonsignaling information is superposed on a main information in a multiplex communication system.
379, Telephonic Communications,
37+, for protective signalling over a telephone line, subclasses 90+ for the combination of a diverse system of current transmission and a telephone system, subclasses 108+ for alternative use of a telephone or a telegraph over the same line.
