FR2765432A1 - Facsimile call rerouting mechanism for telephone subscribers - Google Patents

Abstract

The facsimile call rerouting mechanism has a unit (5) placed in the incoming telephone line. The unit examines the frequency of incoming calls before the telephone line is lifted up. If the frequency is above a set threshold, a facsimile message has been detected, and the call is rerouted (6) to a central facsimile machine. If a facsimile call is not detected, the signal voltage level is increased (7) and passed to the call unit, at a representative telephone level.

Description

 The present invention relates to a device making it possible to detect and eliminate calls transmitted over the telephone line of a subscriber, but not intended for the latter, in particular calls originating from a fax transmitting station.

 Many telephone subscribers have the annoyance of receiving calls on the line allocated to them from fax transmitting stations, on which the number of the called station has been wrongly numbered due to an error in recording the reference numbers of the real recipient, setting off the ringtone for this extension, the subscriber thus called, after picking up his handset, obviously receiving no audible message.

 Many fax machines are equipped with programming systems, allowing their user, by operating the station as a transmitter, to automatically defer, to the receiving fax machines of several subscribers to be successively put into communication, an advertising or other message, the transmission of which generally takes place at night to benefit from advantageous rates. In addition, these programming systems are provided such that, in the event of busy or correct malfunction of a receiving fax machine, the sending of the message is repeated at regular time intervals.

 Therefore, if among the stations called in sequence, there are one or more badly programmed numbers, the subscribers whose real numbers correspond to these, are disturbed by the ringing of their station, at times which can be particularly annoying.

 Under these conditions, the advantage of a device for detecting a call from a sending fax machine, intended for a call number corresponding to the usual telephone line of a subscriber, therefore poorly programmed, which he is a particular call or even more of an implementation by an automatic system where the number in question will be called several times, is obvious.

 Some systems already exist at present to detect a call signal from a subscriber receiving station originating from a facsimile transmitting station, these systems having the disadvantage of isolating the subscriber line for a certain period when the message from the improperly programmed fax machine is directed and received by a fax machine specially installed at the subscriber's place, frequently disturbed, in order to identify the origin of the erroneous call.

This solution is impractical and involves intervention by the telephone operator and therefore additional constraints and costs for the operator and his client.

An improvement can consist for the subscriber in activating a function called IAM ("Call Indicator
Malicious "), although this function is reserved for certain security services. However, the implementation of this function is not particularly simple, the subscriber in particular having to operate the" R "key on his terminal, which requires firstly that it has a so-called keyboard & voice frequencies. In addition, experience shows that subscribers, often disturbed in their sleep under the conditions mentioned above, do not always have the reflex to trigger this key and hang up their handset immediately, eliminating any possibility of detecting the number of the wrongly programmed sending fax machine.

 Finally, assuming that the above function has been properly implemented, the sending fax machine being forwarded to a specialized fax machine, it may turn out that the first is part of a grouping, connected to an Enterprise switch, precise identification of this device is therefore often impossible.

 The present invention relates to a device which avoids users of such a drawback, by eliminating any unwanted call from a sending fax machine and by automatically directing it to a receiving fax machine, specially dedicated to such reception and located at the telephone exchange to which it is connected. the line of a subscriber, so that the number of the sending fax machine from which the incorrect call originates can be identified without disturbing the recipient whose call number has been programmed incorrectly, before then taking the measures necessary so that the initial error does not occur again, in the interest of the subscriber as well as the user of the sending fax machine.

 To this end, the device considered, placed in series on the usual telephone line of a subscriber, in particular at the level of its connecting strip to the telephone network, is characterized in that it comprises an assembly suitable for detecting, after lifting the handset of the called station, the frequency of the carrier of the calling signal, then to compare this frequency with a reference threshold and, in case this frequency is higher than this threshold, signifying that the call comes from a transmitting fax machine, to isolate the called station and to return this call by a connection line with a specialized fax machine, located outside the called station, or vice versa, if the frequency is lower than this threshold, to let pass the signal intended for the station called, the voltage level of this signal being increased in this case in a supply circuit mounted between the detection assembly and the called station, so that this sign al is returned without weakening to the subscriber, at the exit of this set.

 Other characteristics of a device for detecting and eliminating unwanted calls originating from facsimile machines, established in accordance with the invention, will become more apparent from the following description of an exemplary embodiment, given by way of indication and not limiting, with reference to the single Figure of the accompanying drawing which is a block diagram of the circuit used.

 In this diagram, the reference 1 designates the end of the line of a telephone subscriber, connected to a conventional switching center (not shown), the opposite end 2 of this same line being connected to the usual telephone set of this subscriber. .

 According to the invention, there is mounted between the connecting strips, respectively horizontal 3 and vertical 4, which ensure the connection of the line to the telephone network, a set 5 allowing, in the event of a call from the subscriber's station, before that the ringing of this extension was not triggered due to the alternative call signal transmitted on the line, and that the user has therefore lifted his handset, to detect the carrier frequency of this signal and to compare this frequency with a predetermined reference threshold, recorded in this set.

 In the event that this frequency is higher than this threshold, which means that the call passing on the line comes from a transmitting fax machine, the subscriber's telephone number having been incorrectly trained or programmed on the extension of this fax machine, the assembly 5 automatically switches the signal to a specialized receiving fax machine, not shown, this signal being routed thereto by a line 6.

 Advantageously, this receiving fax machine is located at the telephone exchange on which the subscriber's line depends, so that it receives the misdirected message and makes it possible to identify its origin in order to notify the sender and to be taken the necessary measures by correcting the incorrect telephone number.

 In the case, on the other hand, where this frequency is lower than the threshold provided, that is to say when it is indeed a normal call signal, intended for the subscriber station called, all of detection 5 lets this signal pass without interrupting the line.

 Preferably, the signal in this case passes through a boost circuit 7, making it possible to increase the level of this signal and to eliminate the effects of the attenuation which it undergoes when crossing the assembly 5, until & a value such that the subscriber is placed in conditions exactly similar to those which would be achieved in the case of a direct transmission of this signal.

 Note that, when the subscriber picks up his own handset to use his line and form any number from his extension, it is necessary to operate a given key on his keyboard, allowing him to resume his line in the event that it has been isolated by the device, due to an erroneous call from a fax machine, as indicated above.

 A device is thus designed which is very simple but which has particularly appreciable advantages, in particular by eliminating a non-negligible number of subscriber complaints, the demands of which are increasing at present with the number of fax machines available and their programming possibilities. .

 This device also allows the telephone operator to directly notify the owner of the wrongly programmed sending fax machine to have & correct the misused number, by providing the subscriber with a particularly timely complementary service.

 Of course, it goes without saying that the invention is not limited to the example of embodiment more particularly described above with reference to the accompanying drawings; on the contrary, it embraces all its variants.

Claims (2)

 1 - Device for detecting and eliminating unwanted calls from fax machines, placed in series on the usual telephone line (1, 2) of a subscriber, in particular at the level of its strip (3, 4) for connection to the telephone network, characterized in that it comprises an assembly (5) suitable for detecting, before lifting the handset of the called station, the frequency of the carrier of the calling signal, then & comparing this frequency with a reference threshold and, in the if this frequency is higher than this threshold, signifying that the call comes from a sending fax machine, isolating the called station and sending back this call by a connection line (6) with a specialized fax machine, relocated vis- & - screw of the called station, or vice versa, if the frequency is lower than this threshold, and let pass the signal intended for the called station, the level of the voltage of this signal being in this case increased in a supply circuit (7) mounted é between the detection unit and the called station, so that this signal is restored without weakening to the subscriber, at the output of this set.  2 - Device according to claim 1, characterized in that the subscriber's station is arranged to produce a line recovery signal, when the latter has been isolated in the event of implementation of the detection assembly.