AU687924B2

AU687924B2 - Activation circuit of telephone subset

Info

Publication number: AU687924B2
Application number: AU81515/94A
Authority: AU
Inventors: Gerard Languille; Claude Malaurie
Original assignee: Alcatel NV
Current assignee: Alcatel Lucent NV
Priority date: 1994-01-12
Filing date: 1994-12-16
Publication date: 1998-03-05
Anticipated expiration: 2014-12-16
Also published as: FR2715018A1; NZ270199A; EP0663754A1; FR2715018B1; AU8151594A

Description

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ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "ACTIVATION CIRCUIT OF TELEPHONE SUBSET" The following statement is a full description of this invention, including the best method of' perlormring it known1 to US:- This invention relates to a device for actuating at least one telephone data receiver, to enable this receiver to receive the data transmitted via the telephone line to which the telephone is connected, before pick-up, i.e. before actuation of the connection unit, which usually consists of a hookswitch or electronic equivalent, enabling the user to establish a call via the telephone line by means of the telephone terminal.

It is a known practice to transmit information data, conventionally grouped in packets, to the called telephone terminal before the call is answered such that the called party may be aware of the origin of this call.

This implies that the called terminal be fitted with some means of supplying power to the circuits involved with the acknowledgment of the information data packets such that they may operate under the conditions specified for such calls.

But conventionally, a telephone terminal will not be supplied power by the telephone line from which it is remotely powered as long as the switching unit S fitted in this terminal for call establishment purposes has not been actuated to this end. Hence, in the absence of specific arrangements, it cannot receive information data via the line.

It is therefore necessary to provide a specific actuation device in any telephone terminal authorising reception of information data via a telephone line before pick-up, It is known to associate the telephone terminal with additional means of power supply such that this terminal may operate when the remote power supply from the telephone line servicing this terminal is insufficient or inoperative. These additional means usually supply power to the terminal from the electrical distribution mains in the premises where this terminal is installed, or from batteries or an accumulator generally integrated to the terminal.

Nevertheless, implementation of such additional means is not systematic and is not necessarily the best possible solution.

According to the invention there is provided a device for actuating at least one telephone data receiver, such that said receiver may receive the data transmitted via the telephone line to which the telephone is connected, after a 3 characteristic call signal has been detected by an alarm circuit arranged to awaken the terminal, but before pick-up, i.e. before actuation of the connection unit enabling the user to establish a call via the telephone line by means of the telephone terminal, wherein said actuation device is fitted with some means of remotely supplying power to a power storage device via the line and via a switching module of the connection unit, while said unit is in the on-hook position and idle, said actuation device being provided with an actuation circuit which is directly or indirectly controlled by the alarm circuit upon reception of a characteristic call signal coming from the line, said actuation circuit including insertion means to connect an impedance having a chosen value, in series with the telephone line at telephone terminal level, said actuation circuit further including means of controlling the supply of power from the storage device to the data receiver at least, during data receiver operating phase, after call detection and before pick-up.

i In order that the invention may be readily carried into effect, S embodiments thereof will now be described in relation to the accompanying drawings, in which: Figure 1 shows the diagram of an example of telephone terminal fitted with a device in accordance with the invention.

N Figure 2 shows the diagram of a device in accordance with the invention assumed to be applied to figure 1 telephone terminal.

Telephone terminal shown in figure 1, which may be a telephone set for instance, is to be connected to the conversation wires of a telephone line via two connection terminals (L1, L2). This telephone terminal contains an input circuit designed to supply the telephone terminal with the power coming from the telephone line and to protect the telephone terminal against dangerous electrical interferences that may be transmitted via this line. It also contains an alarm circuit which is a type of ring circuit, connected to the telephone line when the terminal and the line are not in communication, this alarm circuit (3) detects the characteristic signal sent via the telephone line to the terminal to indicate an incoming call.

The telephone terminal is also fitted with a connection unit under the control of the terminal user enabling the latter to establish a call via the telephone line. As previously mentioned, this connection unit may for instance be of the type commonly called hookswitch or its electronic equivalent, in this instance it is assumed to be fitted with two separate switching modules (CC1) and (CC2) which are controlled simultaneously and illustrated herein by two sets of contacts.

According to a conventional method of implementation, the first switching module (CC1) in the connection unit is used for the electrical connection of one terminal (L1 in this instance) to the input circuit when the connection unit is actuated, and to the alarm circuit when the connection unit is idle and in the on-hook position, in the absence of a call.

Alarm circuit is connected to terminals (L1) and via switching module (CC1) for the latter, when the connection unit is in the on-hook position, it is designed to detect the presence of a characteristic call signal, which may for instance be an a.c. ring signal transmitted during a set time lapse and with a S preset frequency.

A capacitor suppressing the d.c. component remotely powering the terminal via the telephone line is then conventionally inserted between alarm circuit and this line, in this example it is between this circuit and terminal Actuation of the connection unit, following pick-up or equivalent, results in the alarm circuit being switched off by switching module (CC1), Alarm circuit which triggers call signalling (usually by means of an audible signal at least) at terminal level if an incoming call has been detected, is also used to trigger the actuation device in accordance with the invention, as will be detailed later.

Input circuit is permanently connected to terminals (L1) and (L2) irrespective of the connection unit status and more specifically of switching module (CC1) status In the first implementation alternative, it is envisaged that a current limiting component connect input circuit to terminal in addition to the connection established by switching module (CC1), when the connection unit is actuated. This limiting component consisting of a resistor, then s I enables the telephone terminal, while the connection unit is in the on-hook position, to avail itself of a fraction of the line current which is available to it when the connection unit is active.

In the second implementation alternative, it is envisaged that there be a permanent direct connection between input circuit and terminal this direct connection being shown in a dotted line across block 5 in figure 1.

Most of the various telephone terminal circuits are designed to be supplied with power from the telephone line via input circuit and the second switching module (CC2) in the switching unit, when the latter is actuated. Most of the time, these circuits contain at least one 2-wire-4-wire transmission circuit and a terminal supervisory logic this logic being built around a microcontroller associated with a memory assembly (not illustrated).

It is envisaged to enable the telephone terminal to receive at least one data packet transmitted by the line, before pick-up, i.e. before actuation of the :1 terminal connection unit, it is planned to have a data receiver available, this receiver being of the type fitted in modems to take into account the data S transmitted. It is also planned to have an actuation circuit (10) such that the data receiver may operate under standard conditions, before the telephone terminal connection unit is activated and at least during a time lapse corresponding to the time required by the receiver to acquire one transmitted data packet. It is also planned to have a display (a liquid crystal display for S° instance) to transmit to the terminal user the information received in the form of a packet by the data receiver in this instance, the information is assumed to S. be transmitted from this receiver to the display via a supervisory logic as is 5 common practice in this regard.

The actuation circuit (10) is one of the main components of the device in accordance with the invention which is briefly summarised in figure 2 which only illustrates the telephone terminal components directly related to the present invention together with the components connections involved during operation of this device. As previously mentioned, the device in accordance with the invention implies that the telephone terminal be fitted with an alarm circuit (3) capable of detecting a characteristic trigger signal which is likely to consist of an ac call signal, having a preset frequency and transmitted by the telephone line to the alarm circuit while the terminal switching unit (CC1) maintains this circuit connected to the line. The connection unit of the terminal fitted with this module is then in the on-hook position.

Alarm circuit is arranged to generate a trigger signal intended for the actuation circuit (10) of the data receiver when it receives a characteristic call signal. This signal may be generated by conventional, simple logic type, triggering devices which are not described further. In this instance, these triggering devices are assumed to act on the actuation circuit (10) via the terminal supervisory logic This logic is assumed to be fitted with an auxiliary power supply device enabling it to operate when it does not receive any line current via switching module (CC2), while the connection unit housing this module within the terminal is idle. The auxiliary power supply device may belong to the logic proper as is common knowledge, or it may be the one S supplying power to the data receiver when the above mentioned connection device is idle, all this not being shown in the figure for simplification purposes S" since the expert in the field can easily implement it.

It is envisaged that actuation circuit data receiver and any other circuit required for their operation such as terminal logic if necessary be D powered by a leakage current supplied by the telephone line to the terminal, when the terminal connection unit is idle and does not provide for normal power supply to the terminal circuits not mentioned above, via switching module (CC2).

To this end, as indicated above, it is planned to have an auxiliary power S*26' supply connecting at least actuation circuit (10) and data receiver to terminals (L1) and when the telephone terminal connection unit is not actuated.

In the proposed example of implementation, the diode bridge usual in an input circuit is directly powered by the line via terminals (L1) and (L2) to which it is connected via its fed terminals and under the above mentioned conditions. Data receiver and actuation circuit (10) are connected to an earth potential assigned to one of the feeder terminals of diode bridge this receiver and this circuit are also connected to the positive feeder terminal of this bridge via a wire called positive feeder wire, via switching module (CC2), when the connection unit is idle, Switching module (CC2) supplies power to the other telephone terminal circuits in particular circuits (6) and and if required to data receiver according to an arrangement not shown in figure 2 that may be implemented in the usual way, when the connection unit is actuated.

The trigger signal, supplied when alarm circuit has detected a characteristic all signal, is translated by the telephone terminal logic into a control to supply power to the data receiver, and into a control to insert an impedance at the line terminals such that the data may be transmitted by the line to the telephone set under the required standard conditions.

Here, the impedance insertion control supplied by logic is applied at the base of an NPN transistor its emitter being connected to the earth ~potential and its collector being connected via wire to the positive feeder terminal of diode bridge via an impedance. Here, the impedance is made up by a d.c component suppression capacitor (12) in series with a resistor (13) which practically corresponds to the impedance which must exist at the telephone line terminals in order to provide for correct data transmission from this line to the telephone terminal. As is common knowledge, a data packet may contain data identifying the calling telephone terminal as well as data providing information on the call, such as call date and time for instance, these data may .O..li be transmitted in a standard telephone transmission code, standard V23, DTMF or other codes for instance. The data in a packet transmitted via the telephone .ooo line to the terminal is conventionally communicated to the data receiver via a diode bridge to which this receiver is connected at terminals and via wire and switching module (CC2), at least when the connection unit housing this module is idle, with regard to the latter terminal. A dc component suppression capacitor (14) and a resistor (15) connect the data receiver to the positive feeder wire The control to supply power to data receiver and eventually to the other telephone terminal circuits required for the operation of the data receiver, I II is applied by logic to a PNP transistor (16) via a resistor This transistor (16) is connected via its collector to a positive feeder terminal of the data receiver and eventually to other telephone terminal circuits which are similarly powered. It is also connected via its emitter to an energy storage device (18), such as a capacitor, which is connected to the positive feeder wire as well as to the earth potential.

Hence the storage device (18) is fed with a leakage current transmitted from the telephone line to the telephone terminal, when its switching unit is idle. The leakage current value is set for instance by a current limiting resistor inserted between wire and the point common to the storage device (18) and the emitter of transistor A Zener diode (20) mounted in parallel with the storage device (18) is used to limit the maximum voltage acceptable at the terminals of these devices and of the circuits they feed. The storage capacity of device (18) is defined taking into account the current required by data receiver to receive data of at least one complete packet before the supply of power to the whole of the telephone terminal circuits occurs by S actuation of the terminal connection unit. If "IR" corresponds to the current required for the operation of data receiver "td" to the duration planned for the reception of one packet, and "Vdc" to the voltage drop acceptable by the receiver, then the storage device capacity "CA" must be at least equal to IR.td/DVc. Preferably, the leakage current used to recharge storage device (18) S while the telephone terminal connection unit is idle, is selected such that the o:ooo data transmitted to data receiver transits without distortion via diode bridge of input circuit If "VD" is the data signal efficient voltage, the ••go impedance presented at the line by the telephone terminal, as mentioned above, and a positive coefficient, then leakage current "IF" must be at least equal to K. /VD. r2 Z as is common knowledge.

According to an alternative implementation planned if the leakage current available is weal< and insufficient to polarise diode bridge in order to ensure correct data transmission, it is planned to connect receiver to terminals (L1) and (L2) via a differential connection thus avoiding the diode bridge during data transmission. This connection is then established under the control of a static I r I In-- 9 relay controlled by supervisory logic if a call was detected by alarm circuit In an example not illustrated herein, it is planned to connect data receiver via a differential connection having two parallel branches. Each of these branches has a capacitor and a resistor in series and each one is connected to one of the extremities of a resistor, corresponding practically to impedance (Z) to be supplied at the telephone line terminals to ensure correct data transmission. This resistor corresponding to is itself connected at one end to terminal (L1) via a capacitor, and at the other end to terminal (L2) via a static relay switching module, the latter being conducting and enabling power to be supplied to the receiver, when the static relay housing it is actuated by supervisory logic Additional modifications must then be made to figure 2 diagram, the branch containing capacitor resistor (13) and transistor (11) S being superfluous in such F circuit, and similarly, the branch containing capacitor (14) and resistor

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Claims

1. A telephone terminal including at least one data receiver and actuating means to actuate the data receiver, the telephone terminal including an alarm circuit to a characteristic cell signal adapted to awaken the terminal, the data receiver bring adapted to receive data transmitted via the telephone line to which the telephone terminal is connected after a said characteristic call signal has been detected by the alarm circuit and before actuation of a connection unit which enabts a user of the telephone terminal to establish a call via the telephone line; 10 the actuation means including remote power supply means to supply power to a power storage device in the telephone terminal via the telephone S" line and via a switching module of the connection unit wile said unit is in the on-hook position and idle; 1 the actuation means including an actuation circuit which is directly or indirectly controlled by the alarm circuit on reception of a said characteristic call signal, the actuation circuit inclitding insertion means to connect an impedance having a predetermined value in series with the telephone line; the actuation circuit including power control means to control the supply of power from the storage device to at least the data receiver during its operating phase after call detection and before actuation of the connection unit by the user.

2. A telephone terminal as claimed in claim 1, fitted with a supervisory logic, the impedance having a predetermined value including a resistor in series with a capacitor, and connected in series with the telephone line while the connection unit is idle, wherein, the insertion means, such as transistors, are actuated by the supervisory logic under the action of the alarm circuit, when a call is detected.

3. A telephone terminal as claimed in claim 2, wherein power control means are actuated by said supervisory logic under the action of the alarm circuit when a call is detected, to temporarily connect the storage device to the data receiver at least, such that the latter may be powered in order to receive said 11 data via the turm of a data packet relating to the call detected.

4. A device substantially as herein described with reference to Figures 1 2 of the accompanying drawings. DATED THIS ELEVENTH DAY OF DECEMBER 1997 ALCATEL N.V. c. S a* MENINOMMUNIA., I 7r r* rley ABSTRACT A device for actuating a telephone data receiver capable of receiving data transmitted via a telephone line, before pirk-up. The device is fitted with means to remotely supply power to a power storage device (18) via a telephone line and via a switching module (CC2) of the telephone terminal connection unit, while this unit is in the on-hook position and idle. The device is also fitted with an actuation circuit (10) which is controlled by the alarm circuit of the terminal, upon reception of a characteristic call signal coming from the line, the actuation circuit being fitted with some means (11) used to connect an impedance having a chosen value, in series with the telephone line at telephone terminal level, it being also fitted with some means (16) of controlling the supply of power from the storage too device to at least the data receiver, during its operating phase, after call detection and before pick-up. 4:06: Figure to be published: Fig. 2 o* S s.. 0 0