TELEPHONE SWITCHING AND FORWARDING SYSTEM

• US 3,704,346 A
• Filed: 01/28/1970
• Issued: 11/28/1972
• Est. Priority Date: 01/28/1970
• Status: Expired due to Term

• Current Assignee: James B. Scott, Lloyd M. Smith, William H. Wertz
• Original Assignee: James B. Scott, Lloyd M. Smith, William H. Wertz
• Inventors: Smith, Lloyd M., Scott, James B., Wertz, William H.
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): Stewart, David L.
• Application Number:
  US05/006,487
• Time in Patent Office: 1,035 Days
• Field of Search: 179/18BA,18BE,18BD,5P,84L,84R
• US Class Current: 379/157
• CPC Class Codes: H04M 1/006 Call diverting means

Abstract

Described herein is a call diversion system for receiving a telephone call, dialing out a different number through a second line and linking the two lines. When identification is needed, an identification code is likewise transmitted subsequent to dialout. A conversation monitor detects absence of communication to permit a timer to run for testing whether temporary interruption of a line evokes dial tone to reset the system. The number to be dialed out can be reprogrammed locally or remotely by sending signals into the system. The number to be dialed out is held in a memory having, for example, individually addressable locations. Automatic dial-out proceeds by a counting process for accurately timing dial pulses and pauses. During operation memory address sequences alternate with dial tone search phases. A subscriber can initiate an immediate dial-out from a remote location. The system diverts calls immediately in the operate mode but defers diversion in the standby mode, giving the user opportunity to answer the phone directly.

Claims

1. An automatic telephone switching system for connection to two telephone lines of a subscriber, leading to a central exchange, and for switching calls coming through a first one of the lines as outgoing call of the second one of the lines comprising:

a ring detector connected to the first one of the lines and detecting persisting low audio frequency signals in the first one of the lines;

first circuit means connected to the ring detector and closing a circuit on the second line when the ring detector has responded to a ringing signal;

tone detector means connected to the second line when closed by operation of the first circuit means and responsive to the envelope of low speech frequency signals coming through the second line and having amplitude above a particular amplitude, and providing first output signals representative thereof;

integrating means connecting to the tone detector means to integrate the first output or a representation thereof, to monitor persistence of the envelope above the particular level for a predetermined period of time in representation of a dial tone as distinguished from other audio signals such as speech and producing a second output as representation of detection of a dial tone;

storage means for holding manifestations in representation of a telephone number;

second circuit means connected to the storage means and to the tone detector for feeding dial pulses in response to the manifestations in the storage means, into the second line subsequent to closing the circuit on the second line by operation of the first circuit means and in response to the second output of the integrating means;

third circuit means connected to be responsive to completion of operation of the second circuit means to interconnect the first and second lines;

the tone detector connected to be responsive to the envelope of signals transmitted through the third circuit means;

a timing circuit connected to the tone detector to be reset wich each first output signal but providing an output if not reset for a predetermined period of time, further connected to the third circuit means to briefly interrupt connection to the first line; and

means connected to be responsive to the second output of the integraTing means to control final disconnection of the first and second lines if dial tone is detected subsequent to operation of the third circuit by the timing circuit.

2. A system as set forth in claim 1, including means for controlling the operative duration of persistence of the monitored signal for dial tone recognition to be shorter, when monitoring dial tone subsequent to operation of the first circuit means than after operation of the third circuit means.

3. A system as set forth in claim 1, the ring detector including a circuit element connected to the first line to be responsive to signals on the line exceeding particular amplitude, and means nongalvanically coupled to the circuit element and producing pulses when the element responds, and including second integrating means for integrating pulses of a continuous sequence above the maximum number of dial pulses in a dial pulse sequence ringing detection occurring only when the number of pulses integrated in a sequence exceeds said maximum number.

4. A system as in claim 1, including a second timer connected to begin running subsequent to ring detector response and providing a temporary opening of the connection to the first line independently from the tone detector means.

5. In a system as set forth in claim 1, the first means including externally settable storage means to store manifestations of dial pulses.

6. In a system as set forth in claim 5, the first means including means providing timing signals on a repetitive basis and at particular frequency, the storage means providing signal indications in response to which the timing pulse providing means are coupled to the second line by operation of the second circuit means for providing a plurality of dial pulses thereto the number of the plurality being determined by the signal indications.

7. In a system as set forth in claim 1, the first means including means for storing signal manifestations of dial pulses, the system further including means (a) for changing the stored signal manifestations in response to input signals, and means (b) for receiving such input signals.

8. In a system as set forth in claim 7, the means (b) connected to one of the lines to receive the input signals through one of the lines.

9. In a system for telephone communication, the combination comprising:

first means at a first location for connection to two subscriber lines for directly interconnecting the two lines in response to a call coming in through one line;

second means connected to one of the lines in response to a call coming in through that one line for receiving signals having a particular characteristic and coming in through that one line during the call;

third means responsive to the particular characteristic of the signals thus received to provide a sequence of dial-out pulses corresponding to said signals to leave the first means through one of the lines;

means responsive to completion of providing of dial-out pulses to obtain an interconnection of the two lines.

10. In a system as set forth in claim 9, the second means including temporary storage means for representation of the signals, the third means operating in response to a call made to one line subsequent to the call during which the signals were received by the second means.

11. In a system as set forth in claim 9, the third means operating in immediate response to the signals as received by the second means to send the dial pulses through the respective other line.

12. In a system as in claim 9, including a transmitter for transmission audio signals of particular frequency for operation at a second location from which communication with the first means at the first location has been established through regular telephone line communication, the transmitter providing a particular sequence of audio signals for transmission to a telephone receiver at the second location, the transmitter operating in response to telephone number digits set into the transmitter, the thIrd means including means responsive to the particular audio signals as received through the one line.

13. In a system as in claim 9, the third means responsive to particular signal components arriving through the one line, such components resulting from continued dialing at a second location after regular telephone communication has been established between a phone at the second location and the one line.

14. An automatic telephone switching system for connection to two telephone lines of a subscriber leading to a central exchange and for switching calls coming in through a first one of the lines as outgoing call of the second one of the lines comprising:

memory means for holding manifestations representing telephone number digits;

first means connected to respond to ringing signals in one line to inititate sequential readout of the content of the memory means as to the manifestations representing the several digits;

second means providing a source of timing signals represented by accurately spaced alternating dial pulses and dial pulse pauses;

third means for coupling the second means to the second line to provide dial pulses thereto corresponding to the manifestations as read from memory, separately for each digit so represented;

fourth means connected to interconnect the two lines subsequent to completion of the memory readout;

fifth means connected to the second one of the lines to be responsive to calls coming in through the second one of the lines to establish a memory loading state for the memory means;

sixth means connected to the second one of the lines for being responsive to a particular characteristic of signals arriving through the second one of the lines and processing the particular signals to obtain a new number to be stored in said memory means; and

seventh means connected to the sixth means for storing manifestations of the new number in lieu of the number digits held therein prior to response of the fifth means.

15. A system as in claim 14, the third means including a register to stepwise receive the content of the memory, digit for digit, as represented by the manifestations;

the second means including a source of accurately spaced timing signals represented by alternating dial pulses and dial-pulse-pause for modifying the content of the register after each reading step until a particular count state in the register has been reached.

16. In a system as in claim 14, the sixth means being responsive to incoming signals of particular frequency and interpreting them as dialed-in digits to be processed by the second means for storage by the memory means to serve for dial-out operation.

17. In a system as in claim 16, the sixth means being responsive to pulse modulated carriers, demodulating same and providing pulses in representation of dial-in pulses.

18. In a system as in claim 16, the sixth means being responsive to frequency encoded signals and demodulating same to provide signals in representation of dial-in signals, to signals to have format for being stored in the memory means by operation of the seventh means.

19. In a system as in claim 14, the sixth means being responsive to incoming signals of particular amplitude interpreting them as dial pulses and producing dial pulse signals to be processed by the seventh means.

20. An automatic telephone switching system for connection to two telephone lines of a subscriber leading to a central exchange, and for switching calls coming in through a first one of the lines as outgoing call of the second one of the lines comprising:

a ring detector connected to the first one of the lines for detecting ringing signals in the first line and providing an output in response thereto;

timing means operated in response to a first ringing signal to provide a delayed control signal of a duration extending over a plurality of ringing signals;

first circuit means for closing the circuit on the second line;

second circuit meanS including manual selector means setting a mode of operation and connected for operating the first circuit means to obtain closing of the circuit on the second line either in response to the first output of the ring detector or after the delay of the timing means has elapsed;

third circuit means responsive to operation of the first circuit means subsequent to the delay imposed by virtue of the position of the selector means, to change the mode of operation of the second circuit means to cause the first circuit means to close on the first ringing signals of a later call;

means for feeding dial pulses into the second line subsequent to closing by the first circuit means; and

means for connecting the first line to the second line subsequent to completion of feeding dial pulses into the second line.

21. A system as set forth in claim 20, including a switch operated in response to the first ring signal, the timing means turning the switch off after the timing has run, and means for causing the system to respond to ringing independently from the timing means subsequent to said turn-off.

22. In an automatic telephone switching system for connection to two telephone lines of a subscriber leading to a central exchange and for switching calls coming in through a first one of the lines as outgoing call of the second one of the lines as in claim 1, the ring detection comprising:

first means coupled to the first line and at floating potential relative to ground, to provide an output pulse of essentially constant amplitude in response to each signal excursion in the line exceeding a particular amplitude;

second means coupled to the first means and responsive to the output pulses, to integrate the output pulses and having a small time constant of decay so that a dial pulse sequence with dial pulses following each other at a rate of about 10 cps is insufficient to cause the integration output of the second means to reach a particular value; and

third means connected to the second means and being responsive to the integrator output and providing a first signal when the integrator output is above the particular value and a second signal when the integrator output is below the particular value.

23. In a system as set forth in claim 22, the first means including gaseous bulb connected directly to the first line to provide radiant output when the instantaneous signal amplitude exceeds a particular value;

the first means further including a radiation detector positioned in relation to the bulb to receive the radiation;

the second means including electrical storage means connected to the radiation detector, there being biasing means to cause the storage means to accumulate electric energy when the detector receives a radiant output, there being discharge means to cause the storage means to loose energy when the detector does not receive a radiant output.

24. In a telephone call switching system for connection to two telephone lines of a subscriber leading to a central exchange and for switching calls coming in through a first one of the lines as outgoing call of the second one of the lines, the subscriber facility being at a first location, the combination comprising:

the facility at the first location, including memory means for holding manifestations representing telephone number digits of a particular telephone number;

first means connected to respond to ringing signals in one line to initiate sequential readout of the content of the memory means as to the manifestations representing the several digits;

second means providing a source of timing signals represented by accurately spaced alternating dial pulses and dial pulse pauses;

third means for coupling the second means to the second line, to provide dial pulses thereto, corresponding to the manifestations as read from memory, separately for each digit so represented;

fourth means connected to interconnect the two lines subsequent to completion of the mEmory readout;

means (a) at a second location having telephone lines connected to the central exchange and receiving calls made under the particular number, the means (a) for providing a particular signal to the first location in response to an incoming call as resulting from the dial-out of the particular number at the first location, the particular signal passing via the communication link from the line at the second location to the second line at the first location;

fifths means at the first location responsive to the particular signal for transmitting a particular identification code held in the memory means to the second location via the communication link between the second line and the line at the second location;

means (b) at the second location decoding the identification code and providing an indication representative of the subscriber; and

sixth means at the first location and connected to the fourth means for obtaining interconnection of the two lines at the first location, after transmission of the ID code, thereby establishing a communication link through the fourth means as between the caller on the first line and the line at the second location.

25. In a system as set forth in claim 24, the second circuit means and the fifths means operating the memory means from which in a first phase the manifestation representing the particular number is read out and from which in a second phase the identification code is read out.

26. In a system as set forth in claim 25, the memory means having individually addressable storage locations;

the system further including, at the first location, a phase and memory address counter for controlling addressing of the memory, further including and control means for advancing the phase and address counter to alternate between stepwise advance for sequential readout and waiting phases during which signals of particular frequency including the particular signal are to be received at the first location prior to causing the phase counter to advance to the next number associated again with a memory location to be read.

27. In a system as set forth in claim 26, the signals of particular frequency including dial tone frequency to be received prior to transmitting the identification code the fifth means being also responsive to dial tone reception during interconnection as provided by the fourth means under control of the sixth means, and controlling opening the interconnection for termination of communication.

28. A system as in claim 24, there being means at the first location including manually operable means to operate the first means independently from the detection of ringing signals.

29. In a system as in claim 31, including additional means at the first location connected to the third means and including manually operable means to selectively obtain operation of the third means independently from the ring detector means.

30. In a telephone communication facility wherein a telephone call from a first subscriber line is switched as outgoing call through a second subscriber line by connecting the first and second lines, the improvement comprising:

first circuit means connected to monitor the signal level in the interconnected first and second lines and including a signal envelope detector providing a first output if the envelope is above a particular level for a particular minimum period of time;

a first timing circuit connected to be responsive to the providing of the first output and providing a second output if the first output is provided uninterruptedly for a particular period of time considerably longer than the minimum period;

a second timing circuit connected to be reset by the first output and providing a sampling signal if not reset for a second particular period of time, considerably longer than the minimum period;

second circuit means responsive to the sampling signal to briefly interrupt and reclose thereafter the connection between the first and Second line; and

circuit means for opening the connection between the first and second line for indefinite duration in response to a second output as provided by the first timing circuit, such second output being provided if a dial tone is on one of the lines after the brief interruption of connection by operation of the second circuit means.

31. An automatic telephone switching system for connection to two telephone lines of a subscriber leading to a central exchange and for switching calls coming in through a first one of the lines as outgoing call of the second one of the lines comprising:

memory means for holding manifestations representing telephone number digits;

the memory being organized in individually addressable storage locations each holding manifestations of a digit of the number to be dialed out, the system including memory control means for sequentially addressing the locations for the several digits;

first means connected to respond to ringing signals in one line to initiate sequential addressing of the locations by the memory control means for sequential readout of the content of the locations of the memory means as to the manifestations in the locations representing the several digits;

second means providing a source of timing signals represented by accurately spaced alternating dial pulses and dial pulse pauses;

third means for coupling the second means to the second line to provide dial pulses thereto corresponding to the manifestations as read from memory, separately for each digit so represented;

the third means, including (a) counter means receiving the content of a storage location as addressed (b) first control means for operating the counter means in synchronism with the timing signals as provided by the second means thereby changing the number previously set into the counter means to a particular number, (c) second control means for coupling the second means to the second line for the duration of counting until the counter means has reached the particular number, and (d) third control means for operating the means for addressing subsequent to the counter means reaching the particular number, to obtain read-out of the content the memory location holding the manifestations representing the next digit, the counter means receiving these manifestations; and

fourth means connected to interconnect the two lines subsequent to completion of the memory readout.

32. A system as set forth in claim 31, including means for receiving dial pulses through one of the lines in sequences, each sequence representing a telephone number digit;

sixth means for assembling the pulses of each sequence and processing same to provide manifestations of a number to be stored;

seventh means for loading the number to be stored into the memory means; and

eighth means responsive to completion of a sequence of dial pulses as received to control the memory means for access to individual number locations in the memory means.

33. A system as set forth in claim 31, including sixth means connected to be responsive to completion of memory readout of manifestations representing the number to be dialed out on one line for monitoring reception of a particular signal through the other line;

seventh means connected to be responsive to reception of the particular signal when received through the other line, to operate the memory control means to continue readout of the memory means, the second and third means providing dial pulses as identification pulses into the other line, the fourth means operating subsequently to completion of sending out the identification pulses.

34. In system as set forth in claim 31, the memory means being a hard-wired, manually adjustable storage facility.

35. In a system as set forth in claim 31, the memory means including a plurality of storage cells provided for recording bivalued bits by operation of electrical signals.

36. In a system as set forth in claim 31, the first control means oPerating the counter means for continuing counting from the particular number in the counter means to a second number, prior to operation of the third control means as counter means in accordance with the next memory reading step, and fourth control means connected for inhibiting the second control means during counting from the particular number to the second number for metering a dial pulse sequence pause.