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Class Information
Number: 379/281
Name: Telephonic communications > Centralized switching system > Switching controlled in response to called station addressing signal > Having shared or common switching control > Including registering or storing device for call address signal > Conversion between dial pulse and voice frequency signal
Description: Subject matter which changes the call address signal between a pattern of abrupt variation in a DC signal such as pulses and corresponding tone frequencies and variations thereof.
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7251313 |
Method and system for returning a call based on information in a voicemail message |
Jul. 31, 2007 |
| 6788767 |
Apparatus and method for providing call return service |
Sep. 7, 2004 |
| 5966436 |
Redialing method |
Oct. 12, 1999 |
| 5425096 |
Communication device |
Jun. 13, 1995 |
| 4914690 |
Universal PBX interface |
Apr. 3, 1990 |
| 4907262 |
Method of transmitting dual tone multi-frequency during communication in a private branch exchange using keyphones |
Mar. 6, 1990 |
| 4868861 |
Trunk dialing converter |
Sep. 19, 1989 |
| 4534027 |
Duplex digital span conversion circuit arrangement |
Aug. 6, 1985 |
| 4311878 |
Dialing interval transmission gating arrangement |
Jan. 19, 1982 |
| 4254304 |
Signal processor for use with a telephone system and a digital transmission line |
Mar. 3, 1981 |
| 4232198 |
Device for establishing conference calls via at least one telephone exchange switching system |
Nov. 4, 1980 |
| 4186278 |
End-of-keying control circuit |
Jan. 29, 1980 |
| 4156115 |
Apparatus and method for a multiple tone code sender system for automatic call initiation |
May. 22, 1979 |
| 4146751 |
Solid state pulsing apparatus for pulsing selected line relay terminals |
Mar. 27, 1979 |
| 4145576 |
DTMF and rotary dial signal receiver |
Mar. 20, 1979 |
| 4093826 |
Tone signaling conversion apparatus |
Jun. 6, 1978 |
| 4013838 |
Telephonic enquiry system |
Mar. 22, 1977 |
| 3988547 |
Telecommunication system having means for converting multifrequency selection signals into digital pulse trains |
Oct. 26, 1976 |
| 3961141 |
Stop time-out until after first DTMF digit dialed circuit |
Jun. 1, 1976 |
| 3946163 |
Port multiplexer for telephone signal processing systems |
Mar. 23, 1976 |
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