US PATENT SUBCLASS 178 / 69 R
.~ Line-clearing and circuit maintenance

Current as of: June, 1999
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178 /   HD   TELEGRAPHY

2 R  DF  SYSTEMS {21}
69 R.~ Line-clearing and circuit maintenance {12}
69 M  DF  .~.~> Frequency measuring and compensating
69 N  DF  .~.~> Precorrectors
69 A  DF  .~.~> Distortion measuring
69 B  DF  .~.~> Interference neutralizing
69 C  DF  .~.~> Balancing duplex cables
69 D  DF  .~.~> Zero wander neutralizers
69 E  DF  .~.~> Leakage compensation
69 F  DF  .~.~> Neutralizing line capactive discharge
69 G  DF  .~.~> Monitoring, alarm and pilot signals
69 H  DF  .~.~> Reiterative
69 K  DF  .~.~> Misc. gas-filled tube circuits
69 L  DF  .~.~> Check back

Unofficial Alpha Subclasses: R M N A B C D E F G H K L

DEFINITION

Classification: 178/69

(under subclass 2) Systems having means for clearing the line of static charges, preventing "tailings", neutralizing the residual magnetism of instruments, neutralizing inductance, adjusting against leakage, and in general maintaining the line circuit in normal condition, and though adapted to capacity or cable systems not limited thereto; also systems having means for preventing the detrimental effects produced by induction from external or internal causes and not specific to any particular system.

SEE OR SEARCH THIS CLASS, SUBCLASS:

3, for automatic telegraph systems.

16, for automatic current reversing systems.

44, for long line type transmission systems and coupling devices therefor.

45, for loaded line systems.

46, for loading coils, per se. 55+, and 58+, for similar means involved in quadruplex and duplex systems, respectively.

63, for combinations of such apparatus in and with specific systems of telegraphy.

SEE OR SEARCH CLASS

307, Electrical Transmission or Interconnection Systems,

89+, for systems of transmitting electricity having means for preventing induction or coupling to other electrical systems.

333, Wave Transmission Lines and Networks,

12, for transmission line inductive or radiation interference reduction systems.

379, Telephonic Communications,

398, and 415 for anti-inductive systems or devices for telephony.