Abstract: Call features for an Automatic Call Distribution (ACD) system implemented within a packet-based telephone environment are disclosed. Within a packet-based network, data messages are transferred between the ACD system and customer telephone stations while the customer waits for an attendant to become available. These data messages allow the customer to be informed of his/her current status within the priority order and further allows the customer to initiate a number of customer oriented operations. These operations include selecting music to listen to while waiting, requesting to be alerted when an attendant becomes available, and initiating a browser session for accessing data information. Overall, the status reports in combination with the initiating of one or more of the customer oriented operations can make the time spent waiting for an attendant a more productive and pleasant experience for the customer.

Abstract: Audibly identifying an event includes enabling selection of a first sound based upon an identifier. The identifier enables identification of an entity related to the event. A notification of an occurrence of the event is received. The notification includes the identifier. An intended recipient is alerted of the event by playing, in response to the notification, at least a portion of the first sound and at least a portion of a second sound that is related to the event.

Abstract: A portable terminal device, which closes AV incoming call notification sound ringing at a headset when incoming call notification sound ringing processing through an AV profile competes with incoming call notification sound processing through a hands-free profile between a cellular phone and a headset, and when an in-band notification mode is set at the cellular phone, connects a sound link to perform communication through the hands-free profile, and starts ringing of an incoming call notification sound through the hands-free profile.

Abstract: A voice notifying service system and a service providing method are provided for a mobile terminal, wherein the voice notifying service system includes a mobile communication system and a mobile terminal for forming a communication channel with the mobile communication system, transmitting voice information, the voice information including a voice and a notifying function for playing the voice, to the mobile communication system, transmitting time information to the mobile communication system specifying the time at which the voice information is to be transmitted to the mobile terminal, and playing the voice information when received from the mobile communication system at the time specified in the time information.

Abstract: Disclosed is a method for setting up a substituted ring back tone (RBT) provided from a predetermined communication provider, and more particularly, a method and system for recognizing a first substituted RBT of a first subscriber and setting up the first substituted RBT as a substituted RBT of a second subscriber, between subscribers of different communication providers. According to the present invention, it is possible to easily copy a substituted RBT from another user's substituted RBT and set up the same as a user's own substituted RBT. In this instance, the substituted RBT is provided according to a request for a call setup of a mobile terminal. Also, it is possible to set up a substituted RBT of a subscriber of a different communication provider as a user's substituted RBT, while not receiving predetermined information from the communication provider.

Abstract: The invention is a provider agent product and method that operates as a software interface between a telephony card and a session manager in an advanced communications network. The provider agent receives event messages from the telephony card indicating on-hook events, off-hook events, and digit events. The provider agent instructs the telephony card to provide dial tone, ring current, ringback, and busy signals to the telephones. The provider agent also exchanges messages with a session manager in the network. These messages include: invite messages, reply messages, join messages, and terminate messages. In response to the above processing, the provider agent instructs the telephony card to interwork telephony signals on a telephony channel with ATM signals on an ATM virtual channel. The provider agent is comprised of a plurality of software objects that are stored on a software storage medium and that include: a controller object, port objects, and event objects.

Abstract: An alert signal of a communication device (1), such as the ring signal of a mobile phone, comprises a set of musical samples that are played by the communication device in sequence. The sequence may be randomly generated, either in response to the event causing the alert or in a set up phase. Alternatively, the user of the device can create a tune to be used as the alert signal by creating a sequence of samples. The user selects samples from a list of samples to create the sequence of samples as individual samples may appear more than once in the tune.

Abstract: A unique system and method that facilitates group-based mobile communication around external feed content is provided. The system and method involve adding external feed content to content generated within a group. Both types of content can be viewed on the mobile devices of the group. Updates to the feed content can be obtained and communicated to the group. When multiple feeds are subscribed to by a group, one or more group members can display such feed content in a selective manner. For example, splinter groups can be formed off of the original group for members who wish to receive a subset of feeds (feed content) to assist them in focusing on a topic of interest. Group members can also employ display filters to restrict feed content displayed on their mobile devices. Users can also search for available feeds and form new groups around such content or join an existing group.

Abstract: Audibly identifying an event includes enabling selection of a first sound based upon an identifier. The identifier enables identification of an entity related to the event. A notification of an occurrence of the event is received. The notification includes the identifier. An intended recipient is alerted of the event by playing, in response to the notification, at least a portion of the first sound and at least a portion of a second sound that is related to the event.

Abstract: The present invention enables an alert message and the display of calling party identity on all on-hook phones associated with an extension sharing the same phone number, when one phone is off-hook and in use. In one exemplary embodiment, this capability enables all other members of a household to receive information regarding an incoming call even when one phone is in use by another member.

Abstract: A main terminal and a method of operating the same. In this method of operating the main terminal, the main terminal is connected to a telephone network so as to communicate with the telephone network, and selectively connects an external terminal to the telephone network. To perform the method, first, if it is requested that the telephone network be disconnected from the external terminal and instead be connected to the main terminal, an internal current to flow into the main terminal is obtained from a loop voltage generated when the external terminal is in connection with the telephone network. Next, the internal current is applied to the main terminal. Thereafter, the telephone network is disconnected from the external terminal and instead connected to the main terminal. While the internal current is flowing in the main terminal, the main terminal maintains the loop voltage generated when the external terminal is in connection with the telephone network.

Abstract: The invention includes a method and apparatus for using a user message from a caller terminal as a call alert for a callee terminal. In one embodiment, a method for providing a user message from a caller terminal as a call alert includes detecting a request at the caller terminal to establish a connection, receiving a user message at the caller terminal and propagating the user message from the caller terminal toward the callee terminal, wherein the user message is adapted for use as a call alert to the callee terminal. In one embodiment, a method for using a user message as a call alert includes receiving, at a callee terminal, a user message associated with a connection establishment request and presenting the user message as a call alert for the connection establishment request.

Abstract: A method to provide a digital notification and response to groups of users comprising storing user contact data for at least one group of users, user selected priority information, and user selected grouping information in a dynamic information database, and using an administrator interface to form at least one message. An administrator initiates transmission of the message simultaneously to a first group of user contact devices for all users in the at least one group of users, then simultaneously to a second group of user contact devices, using the user selected priority information. The administrator interface is used to ensure each user is contacted on the first group of user contact devices before the second group of user contact devices. Responses are received from the user contact devices indicating the devices that received the message and when insufficient user contact device information exists to contact the user contact devices.

Abstract: The present invention, in one aspect, relates to a method for replicating ring back tone (RBT). In one embodiment, the method includes the steps of sending a Play and Collect request to a media resource server (MRS) by an application server (AS), playing an RBT subscribed by the called party to the calling party and obtaining a Replicate RBT request initiated by the calling party according to the Play and Collect request by the MRS, receiving the Replicate RBT request obtained and sent by the MRS, by the AS, and sending a Replicate RBT command to an RBT platform according to the received Replicate RBT request by the AS, the Replicate RBT command carrying RBT replication information and instructing the RBT platform to replicate the requested RBT to an information library of the calling party. The invention also relates to a system and apparatus for implementing same.

Abstract: A digital notification and response system utilizes an administrator interface to transmit a message from an administrator to a special needs contact device and responders contact devices. The system comprises a dynamic information database that includes member contact data, priority information, response data, and grouping information. The administrator initiates distribution of the message based upon grouping information, priority information, and the priority order. The message is transmitted through at least two industry standard protocols simultaneously to groups of contact devices based upon priority information. Once the message is received by the contact device, the contact device transmits a response through the industry standard protocol back to the dynamic information database.

Abstract: A data communication system is disclosed which comprises: first terminal devices for transmitting contents and content provider identification data identifying the providers of the contents; a server device for receiving and storing the transmitted contents and content provider identification data; and second terminal devices which transmit user identification data to the server device, which receive and store the contents from the server device based on the user identification data, and which reproduce the stored contents upon detection of an incoming call. The server device stores first account information corresponding to the content provider identification data and second account information corresponding to the user identification data.

Abstract: A telecommunications device comprises a communication alert system arranged to inform the user that a telecommunications signal has been received. The communication alert system uses one of a number of different indicators. The controller is arranged to control the selection of the one of a plurality of indicators such that the selection is affected by a user selectable component of the received telecommunications signal.

Abstract: A switching apparatus distributes incoming calls to end point terminals that belong to a service group and that interact with the switching apparatus via messages. The messages query the end point terminals by specifying a range and asking those end point terminals that meet a criterion associated with the range to respond. By iteratively narrowing the range, for example, in a binary search fashion, one of the end point terminals is selected. In one embodiment, the range relates to fixed sequence IDs of the end point terminals and the criterion relates to whether an end point terminal is idle or not. In another embodiment, the range incorporates the idle/not idle state of the end point terminals by specifying idle time durations.

Abstract: A school-wide notification and response system utilizing an administrator interface to transmit a message from an administrator to contact devices for parents, employees, and students associated with a school. The system includes an interface with a translator, a call me feature, and a call in feature enabling a customer service representative to use the system to send a message to users. The system has a dynamic information database that includes parent, employee, and student contact data, priority information, and response data. The administrator initiates distribution of the message based upon grouping information, priority information, and the priority order. The message is transmitted through at least two industry standard gateways simultaneously to selected group contact devices based upon priority information. Once the message is received by the contact devices, the contact devices then transmit a response through the industry standard gateways back to the dynamic information database.

Abstract: A data communication system is disclosed which comprises: first terminal devices for transmitting contents and content provider identification data identifying the providers of the contents; a server device for receiving and storing the transmitted contents and content provider identification data; and second terminal devices which transmit user identification data to the server device, which receive and store the contents from the server device based on the user identification data, and which reproduce the stored contents upon detection of an incoming call. The server device stores first account information corresponding to the content provider identification data and second account information corresponding to the user identification data.

Abstract: A mobile telephone comprises a ringer to provide an audible alert of an incoming telephone call. The mobile telephone has a ringer schedule interface to receive a ringer control schedule. The ringer control schedule indicates times at which a parameter of the ringer is to change. The mobile telephone further comprises an integrated ringer controller to automatically change the parameter of the ringer according to the ringer control schedule.

Abstract: Compressed entertainment content such as audio or video or both includes additional aspects and operations associated their way. The compressed audio may be used to signal computers such as a telephone or reminder for an appointment. A melody line may be extracted from the audio, or the audio may be used exactly as it is. Another aspect stores traders within the entertainment content such as in MP3. Those traders are used to trigger the system to retrieve other parts of the content to be displayed at the same time that that particular part of the MP3 is being play. The content may include video or text, or maybe links to other content such as broadband content four times sensitive content. Another aspect describes encryption which is keyed to the disk ID to prevent playing oven illegally copied disk. Another aspect reads a specified amount of information then spins down the disk to conserve battery power.

Abstract: The present invention relates to a ring voltage generation circuit for generating a ring voltage (VTR) between a TIP lead (9) and a RING lead (10) with minimized power loss for electronic subscriber circuits, comprising: a) an amplifier circuit (2) which receives an input voltage (VI) for amplifying the input voltage (VI) to provide the ring voltage (VTR); b) an absolute value generator (3) which receives the input voltage (VI), measures an absolute value (|VI|) of the input voltage (VI) and outputs the measured absolute value (|VI|) of the input voltage (VI); c) a DC/DC converter (4) which receives the measured absolute value (|VI|) of the input voltage (VI) and converts the measured absolute value (|VI|) of the input voltage (VI) into a supply voltage (VSUPPLY) for the amplifier circuit (2); and d) a common mode feedback device (5) which receives the supply voltage (VSUPPLY), a TIP potential (VT) of the TIP lead (9) and a RING potential (VR) of the RING lead (10) and which generates thereof a control volt

Abstract: To make a call, a calling-end terminal station (3) notifies a call-up control unit (71) of a communications network (7) of the terminal station number of a called-end terminal station (5) so as to cause it to stand by for a connection. The calling-end terminal station (3) notifies a calling party information server (9) of the calling-end-terminal-station number and the called-end-terminal-station number and instructs it to transmit to the called-end terminal station (5) calling party information stored in advance for the caller and called parties. The calling party information server (9) transmits the calling party information to the called-end terminal station (5) which in turn instructs the call-up control unit (71) to exit standby mode. This amounts to the communications network (7) calling up the called-end terminal station (5), resulting in the called-end terminal station (5) reproducing the received calling party information to alert the user to the call from the calling-end terminal station (3).

Abstract: A transceiver according to some embodiments of the present invention receives data from a plurality of frequency separated transmission channels from a complementary transmitter of another transceiver and adjusts the power output of certain channels in a transmitter of the receiver. Upon start-up, the power output levels of signals in individual channels in the transmitter can be preset. A power balance can determine new power output levels of the transmitter from parameters in the receiver while receiving data transmitted by a similarly situated complementary transmitter in a second transceiver coupled to the transceiver. In some embodiments, a complementary receiver of the other transceiver determines the power outputs of the transmitter and the power levels are transmitted to the transmitter by the other transceiver.

Abstract: A school-wide notification and response system utilizes an administrator interface to transmit a message from an administrator to a contact devices for employees and parents associated with a school. The system comprises a dynamic information database that includes parent and employee contact data, priority information, and response data. The administrator initiates distribution of the message based upon grouping information, priority information, and the priority order. The message is transmitted through at least two industry standard gateways simultaneously to groups of parent and employee contact devices based upon priority information. Once the message is received by the parent and employee contact devices, the parent and employee contact devices transmit a response through the industry standard gateways back to the dynamic information database.

Abstract: An apparatus in one example comprises a call control component that sets a call category for a call to indicate that the call terminates at an announcement server component prior to connection with a called communication device. Upon receipt of an answer message from the announcement server component, the call control component drops the answer message based on the call category.

Abstract: A telephone system includes a controllable ringing generator for generating a ringing signal and an interface for providing a ringing voltage derived from that signal on the transmission line. The controllable ringing generator includes a control device for controlling the ringing voltage in response to the ringing current.

Abstract: The invention creates a method for adjusting a ringing signal current in a subscriber line (106), a ringing signal generator (114) which generates the ringing signal being connected with one end of the subscriber line (106) and at least one subscriber (102) being connected to another end of the subscriber line (106), comprising the steps of detecting a ringing signal current of the ringing signal; of comparing the detected ringing signal current with a predetermined current value; and when the detected ringing signal current is greater than the predetermined current value, reducing a ringing signal voltage of the ringing signal in such a manner that the ringing signal current is equal to the predetermined current value, the ringing signal voltage being dropped across the subscriber line (106) and a load of at least one subscriber (102). The invention also creates a circuit arrangement for carrying out the method.

Abstract: In a telephone system where frequency multiplexed analog telephone signals and digital data signals are transmitted over a line, incoming calls are announced to the customer installation by a ringing indication signal having an amplitude between 1 and 30 V RMS, which is much less than the regular ringing and therefore easier to be generated, and moreover having a smoother shape than a rectangular shape. Upon receiving the ringing indication signal, the customer installation locally generates and provides a full ringing signal to a telephone. The amplitude of this local ringing signal is higher than the amplitude of the ringing indication signal, but the line with the digital data signal is isolated from the customer telephone equipment at the time the ringing signal is generated, so as to avoid disturbance of the digital data transmission by the ringing current, which is a source of impulsive noise.

Abstract: A ring voltage generator uses values stored in random access memory to generate a train of pulses used to drive a voltage waveform to ring a telephone ringer. The values are stored in RAM, and are programmable by a user without requiring a change in the ring voltage generator design.

Abstract: A method and apparatus is provided reducing false switch hook detection in a line card coupled to a subscriber loop. The method comprises operating in a first state of the line card, receiving a control signal, and disabling switch hook detection in the line card. The method further comprises determining an initial condition of a second state of the line card, operating in the second state of the line card in response to receiving the control signal, wherein the second state begins to operate from the determined initial condition. The switch hook detection in the line card is activated.

Abstract: A power management circuit for a remote access platform extracts power from a wireline for powering a ring generator that generates a ringing voltage signal that is distributed to a plurality of subscriber circuits. A power-limited voltage converter steps up the wireline voltage to a higher ‘isolating’ voltage, charging a capacitor coupled to the ring generator. A monitor circuit reduces the power that the power-limited voltage converter can draw, if the wireline voltage drops too low. This prevents the wireline voltage from collapsing should the remote terminal be deployed at a distance from wireline voltage source (the central office) greater than its specified capability.

Abstract: An apparatus which produces a ringing signal for a telephone system, effectively suppressing impulse noises. A ringing voltage generator produces a ringing voltage. A ringing signal sending unit sends a ringing signal to the called telephone terminal over the subscriber line by outputting the ringing voltage intermittently. This ringing signal consists of ringing periods and silent periods which will appear alternately with a prescribed duty cycle. One of those silent periods is used by a data transfer unit used to transport data to the called terminal. A feed impedance setting unit provides a feed voltage with higher source impedance. A feed impedance selection unit selects a low-impedance feed voltage in the one of the silent periods during which a data transfer is performed, and selects a high-impedance feed voltage in the other silent periods during which no data transfer is scheduled.

Abstract: A method and apparatus for notifying a user of an incoming cellular telephone call are provided. The apparatus includes a cellular telephone body having at least a back surface, a first transducer positioned within said cellular telephone body perpendicular to the back surface and adapted to generate a first acoustic field, and a second transducer positioned coaxially to the first transducer and adapted to generate a second acoustic field. A first frequency generator is coupled with the first transducer to drive the first transducer to generate the first acoustic field and a second frequency generator is coupled with the second transducer to drive the second transducer to generate the second acoustic field in response to an indication that an incoming cellular telephone call has been received. The first and second acoustic fields overlap. The overlapping fields generate a vibrational sensation from a difference of frequency from unequal frequencies generated by the first and second transducers.

Abstract: The present invention comprises an improved telephone system and method that determine the identity of the callee of an incoming telephone call. A distinctive ring is selected by one or more of the users of the telephone prior to activating the feature or at a later time. Information about the individual distinctive ring signals is stored in memory inside the telephone. When an incoming call is received from an external party, the telephone determines which one of the users is the callee of the telephone call. A distinctive ring signal is then generated corresponding to the identified callee of the incoming telephone call. The distinctive ring signal identifies the callee of the incoming telephone call to the telephone users. In order to identify the callee of the incoming telephone call, the telephone system, after answering the incoming telephone call, inquires the caller for the identity of the callee. In another embodiment, a callee is identified using voice recognition techniques.

Abstract: A telephone system includes a plurality of telephone terminals wherein a call that is placed from a calling telephone terminal to a receiving telephone terminal is announced by activating a standard ringing indication at the receiving telephone terminal. A data file is provided having a plurality of different ringing indications therein. These ringing indications include a plurality of sound information that are both different from each other and different from a standard ringing tone, and a plurality of different visual information. When a call is placed from a calling telephone terminal to a receiving telephone terminal, the user at the calling telephone terminal may optionally elect to announce the call at the receiving-telephone-terminal using ringing indication that is selected from the data-file, for example sound information that indicates the identity of the calling-users, and/or visual information that indicates the priority of the call.

Abstract: To reduce the distortion of digital data due to on/off switching of the ringing of a Plain Old Telephone Service (POTS) signal (RINGING1, RINGING2) transmitted simultaneously with the digital data over a single line (LINE), the telephone ringing signal generator (POTS-RING GENERATOR 1, POTS RING GENERATOR 2) produces a digital data friendly ringing signal (RINGING1, RINGING2). The telephone ringing signal generator (POTS-RING GENERATOR 1, POTS RING GENERATOR 2) thereto applies a transient smoothening window (WINDOW1, WINDOW2) to a sine or cosine shaped signal (SINE1, SINE2).

Abstract: An indication of urgency of a call is received from a caller. The urgency indication is communicated to the called party through a distinctive notification, such as distinctive ringing. The urgency indication may be obtained from a caller via a personal agent.

Abstract: An arrangement is provided for digital transmission of information via lines between a line termination (1) of a telecommunication network and subscribers (Tln) connected to the line termination. At least one terminal of a subscriber (Tln) is connected to a network termination (2) via an electric line (L3). The network termination (2) is connected to the line termination (1) via a line (L2) having metallic conductors. The line termination (1) has a voltage source (SV) for supplying power to itself and to the network termination (2) and the subscriber (Tln) terminals. For increased reliability during operation, two separate power supply units (SVE1, SVE2) are arranged in the network termination (2). One of the two separate power supply units (SVE1, SVE2) powers active components of the network termination (2) and the other of the two separate power supply units (SVE1, SVE2) powers the subscriber (Tln) terminals.

Abstract: A direct inward-outward dialing (DIOD) trunk circuit having a DIOD detecting/sending circuit connected to tip and ring terminals connected to a central office line and a primary coil of a transformer, for detecting a polarity of the voltage potential at the tip and ring terminals and the current flowing therethrough to determine reception of one of an incoming and outgoing telephone call, and a switch, controlled by a relay driver responsive to an interface circuit used for interfacing the DIOD trunk circuit with a switching circuit of a private branch exchange (PBX), for enabling the current to flow between the tip and ring terminals through the DIOD detecting/sending circuit via one of a low or high impedance path, wherein the low impedance path is used to establish a speech path between a central office line subscriber and a corresponding extension subscriber of the PBX.

Abstract: Method for improving the calling procedures of telephones by creating customized messages for telephones coupled to a telephone exchange. The messages are registered on one or more sections of memory located in the telephone exchange and coupled to the telephone. The messages can be played over a boosted loudspeaker or the earphone of the telephone. When the telephone is switched on, but is not in communication with another telephone, the ring loudspeaker, if any, and the earphone loudspeaker are deactivated, and the boosted loudspeaker is activated. When a caller telephone receives a call from a caller telephone the activated boosted loudspeaker plays the chosen registered and optionally other messages. When the caller and the called telephone are hooked up, the boosted loudspeaker is deactivated, the earphone loudspeaker is activated and, thereby, placing the caller telephone in communication with said called telephone in the normal way.

Abstract: A call progress monitor circuit is disclosed for a digital DAA in which digital information is transmitted across an isolation barrier from phone line side circuitry to powered side circuitry. In particular, the call progress monitor circuit of the present invention converts oversampled digital transmit and receive data into analog transmit and receive signals and then combines them to produce a call progress signal that is provided to be fed to a speaker driver circuit. In addition, the call progress signal in one embodiment is filtered with a low pass filter. The call progress monitor circuit in one embodiment includes oversampled digital-to-analog converters, a summing circuit, and a low pass filter. Corresponding methods for monitoring the progress of a call utilizing oversampled digital transmit and receive signals are also disclosed.

Abstract: A sonic method of classifying and screening incoming telephone, and other types of calls is disclosed. Based on information from the network provider, such as a caller ID message from a telephone company, distinctive sounds which are easy to mentally associate with specific callers or categories of callers are generated in place of, or in addition to, other call alerting methods, such as the standard ringing of telephones—so there is no need to go to, view, or to be able to read, the caller ID information on a visual display. The invention can be configured to not generate a distinctive sound for certain callers or categories of callers, so calls from certain callers or categories of callers will not disturb the called party. The invention can be connected to any telephone receptacle as a standard telephone or answering machine would be, so no special wiring or installation is required.

Abstract: The invention concerns an integrated computer and telephony system and a method of integrated computer telephony in which at least one main is switch is capable of receiving incoming telephone calls and of dialling outgoing calls. A computer terminal is associated with the switch and means are provided for recognising that a telephone number connected to the switch as an incoming call is associated with said computer terminal; together with and means for causing said computer terminal to give an indication that an incoming call has been received, with the call being held by the switch so that the computer terminal indication is without the telephone being caused to ring.

Abstract: The invention is a provider agent product and method that operates as a software interface between a telephony card and a session manager in an advanced communications network. The provider agent receives event messages from the telephony card indicating on-hook events, off-hook events, and digit events. The provider agent instructs the telephony card to provide dial tone, ring current, ringback, and busy signals to the telephones. The provider agent also exchanges messages with a session manager in the network. These messages include: invite messages, reply messages, join messages, and terminate messages. In response to the above processing, the provider agent instructs the telephony card to interwork telephony signals on a telephony channel with ATM signals on an ATM virtual channel. The provider agent is comprised of a plurality of software objects that are stored on a software storage medium and that include: a controller object, port objects, and event objects.

Abstract: A telephone apparatus connects to a telecommunications network via an exchange line. It has signal recognition for detecting and recognizing calling line identity (CLI) and called number identity (CNI) signalling transmitted over the exchange line. The apparatus causes an incoming call to be transferred to a second exchange line in response to specified CLIs and/or CNIs.

Abstract: Alert amplifier (10) has a peak detector (22) and an operational amplifier (30) that dynamically set a bias voltage of a transducer (32) to minimize the standby current. In the absence of an input ring signal at an input terminal (12), the standby current in the transducer (32) is zero. The bias voltage to the transducer (32) is adjusted from a reference voltage downward in accordance with the input ring signal to minimize the current in the transducer (32) during the activation of the alert amplifier (10).

Abstract: In generating a ringing signal of predetermined frequency and shape between the A- and B-wires to a subscriber's station in a telephone network, the ringing signal is directly injected in or superposed on the DC-levels of the wires. A voltage difference converting device converts any voltage difference between the A- and B-wires into a first current. A signal generating device generates a first voltage of the frequency and shape of the ringing signal to be generated, and a signal converting device then converts the first voltage into a second current. In a summation node the first current is subtracted from the second current to obtain a third current and this current is converted by passing it through a resistor to a second voltage. The second voltage is buffered and is again converted to a fourth current by applying the voltage to resistor. This fourth current is amplified by current amplifiers circuits comprising operational amplifiers, and is then supplied to the A-wire and drawn from the B-wire.

Abstract: The telephone line coupler circuit has a single transmit opto-coupler whose output includes a DC bias component connected to a gate of a line seize switch for connecting a DC line seize load across the ring and tip contacts of the telephone line. The line seize switch is saturated by the transmit opto-coupler bias output and the AC component of the transmit opto-coupler output is sent over the telephone lines. The receive opto-coupler is used both for receiving communications signal and for detecting the ring signal. The band pass filter connected to the output of the receive opto-coupler may be switched to pass a ring signal frequency band or a communications frequency band. The circuit operates using two opto-coupler devices while conventional circuits require four opto-coupler devices.