Calling line tracing system and identification detector

Claim 2

A telephone system including means for identifying a calling station to be connected by way of a telephone exchange to a called station provided with an identification detector device, the exchange being arranged to recognise a station provided with such a device and on receipt of a call for such a station to send a signal to the exchange where the call originated requesting identification information of the calling station and then to transfer control of the call to the identification detector device at the called station, the detector device being arranged to receive the identification information and to control thereby the completion of the call from the calling station to the called station.

Claim 5

A system according to Claim 2 characterised in that the local exchange of the called station is arranged to send a signal to the exchange where the call originated, requesting identification of the calling section before its control unit is disengaged.

Claim 6

A system according to Claim 1, 2 or 3 characterised in that the identification detector device comprises means (1) for sensing the operational state of the receiver of a subscriber station, whether hung up or in use, means (2) for receiving signals from the network (9) and for selecting the standard telephone signal frequencies, means (3) for decoding the selected signals into characters representative of the characteristics of the calling station, means (4) for storing the decoded signals, means (5) for generating telephone frequency signals and for transmitting them to the calling station exchange to acknowledge receipt of said selected signals identifying the calling station and means arranged, after identification of the calling station, for generating a calling signal for transmission to the calling station and a call signal for the called station.

Claim 7

A system according to Claim 4 characterised in that the signals identifying the calling station comprise a plurality of characters arranged in a predetermined sequence and the detector device is arranged to receive the signals, to decode and to store them in said sequence under the control of the telephone frequency generating means (5) whereby each time the means (5) acknowledges receipt of a signal the next character in the sequence is transmitted to the called station until a signal is received by the detector device indicating that all of the characters in the sequence have been transmitted.

Claim 10

An identifying system as set forth in Claim 1 wherein said identification detector comprises: means for sensing the position of the subscriber set receiver, whether hung up or in use, means for receiving the frequencies used for telephone exchange signalling and selecting the standard telephone signalling frequencies from any other frequency present in the telephone network, means for decoding the set of telephone frequencies received into the figures implied in those telephone frequency signals, means for generating telephone frequency signals, means for storing in a memory unit the information encoded in the telephone frequency signals received and decoded by the decoding means, means for retrieving the information accumulated in the memory unit, means for presenting the information accumulated in the memory unit directly or indirectly through intermediate storage in an auxiliary memory, means for generating a signal or current to actuate a loudspeaker or bell to advise the telephone attendant or subscriber that a call is being received, means for generating a calling tone to advise the calling party that the called station has been localised and is being called, means for connecting the sensor of the subscriber set receiver position to the control unit of the identification detector device to cut off the calling tone and called current or signal when the subscriber set receiver has been picked up, that is, when a call has been attended or is being made from the subscriber set, means for automatically isolating the frequency receivers during the sending of return signals through the subscriber line, means for isolating the identification detector device through an interconnecting circuit when the call originates with the subscriber set where the identification detector is connected, means for allowing the processing and completion of a call even in those cases where the identification of the calling party is not received, there being received instead a repeated figure code by the identification detector, which accepts the repeated figure through a counter circuit as the identification of the calling station, means for allowing the processing and completion of call even in those cases where the identification of the calling station is not received, there being received instead a standard unidentified calling number signal, I-12 signal in standard telephone signalling language.

Claim 11

An identification system as set forth in Claim 1 wherein the set of telephone switching exchanges of the network has been specially programmed to have: means for disengaging the control unit of the end telephone exchange of the called party upon receiving a call addressed to a called line designated with a special category or shunt and returning a signal requesting identification of the calling station instead of a signal indicating that the called line has been localised and changing to a code containing information about the state of the line reached, means for stopping or cancelling the sending of calling tone for the caller and called signal or current for the called party, means for transferring the control of the calling process from the control unit of the end telephone exchange to the identification detector, which takes over the control of the calling process until the identification of the calling party is received and the call is completed, means whereby if the exchange of origin where the calling station is connected cannot send the identification of the calling line in response to the identification request signals of the detector, the corresponding tandem exchange has been specially arranged to send instead a repeated code figure which can be accepted by the detector as identification of the calling station, allowing the completion of the call, or alternatively, means whereby if the exchange of origin where the calling station is connected sends a signal that the calling part is unidentified the detector, upon receiving this signal, is internally programmed to complete the call, showing in the display or storing in its memory a predetermined number as identification of the calling party, without any special arrangement in the intervening tandem exchanges, if existing, allowing it to complete the call.

Claim 12

An identifying system as set forth in Claim 1, 8 or 9 wherein the identification process of the directory number of a calling station of a plurality of telephone stations connected through a telephone switching network to a called station is started automatically if, and only if, the local telephone exchange where the called station is connected, upon receiving a call, senses an addressed telephone line which has been designated with a special category or shunt.