Patent Publication Number: US-2017353604-A1

Title: Method of filtering messages to provide a &#34;do not disturb&#34; function

Description:
TECHNICAL FIELD TO WHICH THE INVENTION RELATES 
     The present invention relates generally to the field of communication systems, and more specifically the provision of a “Do Not Disturb” service. 
     TECHNOLOGICAL BACKGROUND 
     The significant expansion of mobile terminals such as mobile phones, “smartphones”, tablets, pagers is accompanied by an intensification of their uses. Today these terminals offer a quasi-permanent connectivity to their users who may be reached at any time. Telephone calls, messages or various notifications may then become very frequent and some users may be bothered by this, describing the use of these terminals as invasive. 
     A simple solution is obviously to switch off these terminals, but this is not always desirable since it then totally excludes any possibility of being reached, even for a possible emergency. Likewise, when placed in “airplane” mode (i.e., disconnected from the communication network), or in “silence” mode, these terminals will not retain the possibility of being reached in case of emergency, the user no longer being notified of calls received. These methods are effective for not being disturbed, but they have the drawback of not offering any adaptability to being reached in case of a possible emergency. 
     Methods or services have therefore been developed to limit the intrusion of these terminals, without, however, entirely excluding the possibility of being reached in case of need. This involves a “Do Not Disturb” service. 
     A service of this type is described in French patent FR9714784. This document describes a system allowing a telephone operator to offer its users activation of a “Do Not Disturb” service at their request. If a user activates the service, then future calls to this user are intercepted—or filtered—by the operator, who informs the caller via a voice message that the user does not wish to be disturbed. Callers, however, retain the possibility of overriding the filtering—via a sequence to be typed on the keys of their telephone—and nevertheless have their call transmitted to the user. The system is therefore based solely on the decision of the caller, who remains the sole judge of the urgency or the appropriateness of disturbing the user. 
     American patent U.S. Pat. No. 5,467,388 describes a system for offering a selective blocking of calls, which can be used to offer a “Do Not Disturb” service. The service offers a user the possibility of configuring a list of privileged contacts (“white list”). When the user activates the “Do Not Disturb” service, the calls from contacts belonging to the white list are transmitted. Conversely, other calls are blocked. The user may also specify access codes. A caller must then provide a correct access code to be placed in contact with the user. The user therefore gains some control over who can disturb them through setting up the white list or the possibility of providing access codes to certain people. 
     The international patent application WO0161978 describes another system for offering a “Do Not Disturb” service. In this system, the user may also configure an access code, a code which will be required from any caller when the “Do Not Disturb” service is active. If the caller supplies the correct code, their call will be directed to the user. Otherwise, the call will be redirected to a voicemail. 
     The preceding solutions, based on white lists or access codes have the drawback of not being able to manage the case of an urgent call from an unknown caller (which therefore cannot have been previously included in a white list, or to which an access code cannot have been previously provided). Unpredictable cases are therefore all filtered by default even though they may sometimes be of an emergency nature. 
     The solutions for providing a “Do Not Disturb” service previously described are in addition intended for voice call communications and are not suited to Short Message Service (SMS) or Multimedia Messaging Service (MMS) messages, for example. 
     Today, therefore, there is a need for a solution for offering a “Do Not Disturb” service, a solution capable of managing the case of unpredictable messages. 
     SUBJECT MATTER OF THE INVENTION 
     The invention proposes remedying the drawbacks previously discussed by providing a method of filtering messages sent by a first terminal, identified by a first identifier, to a second terminal, the terminals being connected via at least one communication network, the communication network including a server connected to a database, the database including at least one first predefined list of identifiers, the server executing the following steps: receiving a first message sent by the first terminal to the second terminal, recording the first message in the database, determining whether the first identifier belongs to the first list and, if so, sending a second message to the first terminal, the second message including a sender field matching a second identifier, or, if not, sending a second message to the first terminal, the second message including a sender field matching a third identifier. 
     Advantageously, it is therefore possible to intercept and record a first message to the second terminal. The user of the second terminal will therefore not be disturbed by receiving the first message on the second terminal, the first message not being received by the second terminal but intercepted and recorded by the server. Indeed, receiving a message on a terminal is often accompanied by a ringtone, vibration and/or visual effect on the screen of the terminal that may be regarded as disturbing at certain times by the user of a terminal. The second message is used to warn the first terminal of the interception of the first message, and therefore its non-delivery to the second terminal. According to whether or not the first identifier—typically a telephone number—belongs to the first list, the identifier of the sender of the second message will be different. It will correspond to a second identifier if the first identifier belongs to the first list or else to a third identifier. This allows a differentiated service to be offered to the user of the first terminal according to whether or not their terminal is identified as belonging to the first list. Indeed, in response to the second message, if the user of the first terminal chooses to respond to this second message, they will therefore respond by sending a message to an identifier that will differ according to the circumstances. The user of the second terminal may therefore, by using the first list of identifiers—e.g. a first list of telephone numbers in a GSM/UMTS context—choose a differentiated response for different users. These users are identified by their telephone numbers, e.g. by putting the numbers corresponding to the terminals of known or priority users into the first list. These users will therefore receive a second message with the second identifier as the sender identifier. 
     According to a complementary embodiment of the present invention, the method includes the following subsequent steps of receiving a third message sent by the second terminal requesting the deactivation of the filtering service provided by the present method and of sending to the second terminal the messages recorded in the database which are intended for it. 
     Advantageously, the user of the second terminal may therefore deactivate the message filtering service according to the present request by sending a third message. Messages sent to the second terminal will then be processed normally, i.e. without interception or recording, once the service is deactivated. All the messages that might be received by the server intended for the second terminal and recorded in the database are then sent to the second terminal. This can therefore be used to delay message reception during the activity period of the filtering service, the recorded messages only being delivered when the user of the second terminal deactivates the service, thus terminating the “Do Not Disturb” period. They then receive any message which they would have been sent during the “Do Not Disturb” period and which would have been intercepted and recorded by the server. 
     According to another complementary embodiment, the method includes the following subsequent steps of receiving a fourth message sent by the first terminal, the recipient field of the fourth message including a fourth identifier, and, if the fourth identifier matches the second identifier or if the fourth identifier matches the third identifier, then a recorded message is retrieved in the database and is sent to the second terminal, or, if not, the fourth message is ignored. 
     The user of the first terminal, after having received a second message in response to their first message, may unblock the sending of their first message by sending a fourth message, a fourth message that has as a destination identifier the identifier corresponding to the sender field of the second message that they have received in return for the first to message sent. The first message is thus unblocked, i.e. it is retrieved in the database and sent to its recipient, i.e. the second terminal. This method may advantageously be used to provide a “Do Not Disturb” service to the second terminal while preserving the possibility of an unpredictable case. Indeed, any user of the first terminal who sends a first message to the second terminal receives in return a second message, whether or not it is previously known, or in other words, whether or not it is previously identified in a first list. This user of the first terminal therefore keeps the possibility of responding to the second message—with full knowledge of the facts—to unblock the delivery of a first recorded message. The user of the first terminal is therefore warned of the “Do Not Disturb” status of the second terminal by the second message, and, if nevertheless it is in their judgment appropriate to disturb the second user, may unblock the delivery of the first message. The delivery of the first recorded message will take place via a fifth message intended for the second terminal. The possibility therefore remains open of reaching a second terminal despite the “Do Not Disturb” status. 
     According to a complementary embodiment, the retrieved message is the last of the recorded messages, sent by the first terminal and intended for the second terminal, the method including a subsequent step of deleting this retrieved message from the database after it has been sent to the second terminal. 
     Advantageously, the server sends the last first message sent by the first terminal to have been recorded in response to a fourth message received from this same terminal, on a principle comparable to a “first in, first out” operation. 
     According to another alternative embodiment, the second message includes a first reference for identifying the first message recorded in the database, the fourth message includes a second reference corresponding to the first reference and the message sent to the second terminal is retrieved in the database thanks to the second reference. 
     Advantageously, this allows a first user who has sent multiple first messages to select the first message to be unblocked—i.e. to be retrieved then sent to the second terminal. The selection is made by indicating a reference in the fourth message, this reference having been provided in the second message. The first recorded messages are therefore not unblocked according to a “first in, first out” mode but according to a selection by the first user, the selection made thanks to the first reference provided in the second message. 
     According to a complementary embodiment, the database includes a second predefined list of identifiers, the method further including the following steps after the to reception of the first message: determining whether the first identifier belongs to the second list and, if so, transmitting the first message to the second terminal without sending the second message. 
     Advantageously, the first messages received from a terminal the identifier of which belongs to the second list are directly transmitted to the second terminal, even though the “Do Not Disturb” service is active for this second terminal. This is particularly advantageous if the identifiers of the second list are particular identifiers such as identifiers corresponding to the emergency services (fire department, hospitals, civil security, etc.) or to certain identifiers previously identified by the user of the second terminal, the messages from these identifiers not having to be filtered. 
     According to a complementary embodiment, the database includes a third predefined list of identifiers, the method further including the following steps after the reception of the first message: determining whether the first identifier belongs to the third predefined list and, if so, recording the first message in the database without sending the second message. 
     In contrast to the preceding embodiment, but in a complementary way, this embodiment can be used to directly record—without sending a second message in return—a first message received from a terminal the identifier of which belongs to a third predefined list. The possibility of unblocking by sending a fourth message is therefore not offered to the first terminal. This is particularly advantageous with regard to identifiers corresponding to “robot” terminals or “automatic message sending servers”. Indeed, these robots are unable to process a second message, and it is therefore pointless to clutter up the communications networks with second messages that would be intended for them. In addition, these robots often respond to messages that are sent to them with an automatic message specifying their robot status and reporting that the message will not be read or processed since it is sent to a robot. A situation could then occur where the robot and the server enter a perpetual loop of sending reciprocal messages. A situation could also occur where since the automatic response of a robot to a second message corresponds to a fourth message, any first message sent by a robot would therefore be automatically—without a validation step by a first user capable of assessing the urgency or appropriateness of disturbing the second user—unblocked to the second terminal. In other words, any robot would short-circuit the “Do Not Disturb” service automatically. The fact of placing the identifiers corresponding to robots in the third list can be used to overcome this. The messages sent by these robots will not therefore be automatically delivered when the second user deactivates the “Do Not Disturb” service. It should be noted that identifiers to corresponding to robots may also be placed in the second list, e.g. a robot corresponding to an emergency service. 
     According to a complementary embodiment, at least one of the second and third identifiers corresponds to a value-added service number. 
     Advantageously the second identifier, the third identifier, or both identifiers, correspond to value-added service numbers, otherwise known as “premium rate numbers”. This creates a deterrent effect since there is then a real cost to disturbing the second user, a cost which takes the form of sending the fourth message to a value-added service number. In choosing a lower cost value-added service number for the second identifier than for the third identifier, or even one of zero cost, the user of the second terminal can encourage users whose identifiers are included in the first predefined list. In contrast, the users of terminals whose identifiers are not included in the first predefined list may have a strongly deterrent cost applied for unblocking their first messages by setting a significant cost for the value-added service number corresponding to the third identifier. 
     According to a complementary embodiment, the messages are of the short message type. 
     According to another complementary embodiment, a message includes at least one short message. 
     Advantageously, the method applies to the exchange of SMS (Short Message Service) short messages or MMS (Multimedia Messaging Service) messages between different terminals. The same SMS message may in fact include multiple SMSs because of the technical limit of 160 characters (according to the coding) for a single SMS. 
     The invention also provides a server implementing the method of filtering messages according to the various embodiments previously described. This server may be partly the second terminal. In other words, the method may be directly executed partly and locally by the second terminal. The interception of a message may then be included through its non-presentation to the user by the second terminal, or a more discreet presentation. For example, for a second terminal including a “normal” mode of presentation of the messages and another “discreet” mode, the first messages will be presented according to the “discreet” mode (respectively not presented) when the fifth messages, corresponding to first unblocked messages, will be presented according to the “normal” mode (respectively to in “discreet” mode). 
     The method for filtering messages sent by a first terminal to a second terminal according to the invention may be implemented in the form of a computer program, this program being executed, for example, by one or more processors of a server connected to a database and to at least one communication network. Consequently, according to one last aspect, the subject matter of the present invention is a computer program comprising program instructions for implementing all or part of the steps of the method for filtering messages sent by a first terminal to a second terminal, when this program is executed by a processor. 
     Moreover, a computer program according to the invention may use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable form. 
     Consequently, the invention is also aimed at a medium for recording information readable by a computer, and comprising computer program instructions according to the invention. Such a recording medium may consist of any entity or device capable of storing such a program. For example, the medium may comprise a storage means, such as a ROM (Read Only Memory), e.g. a CD-ROM or a microelectronic circuit ROM, or a removable recording means, such as a USB stick or a magnetic recording means, such as a hard disk. On the other hand, a software program or module according to the invention may in particular be downloaded from an Internet type network. The advantages provided by a computer program, as briefly defined above, are identical or contribute to those mentioned above in relation to the method for filtering a message sent by a first terminal to a second terminal, and will therefore not be recalled here. 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG. 1A  represents a server for implementing the method in accordance with an embodiment of the invention, 
         FIG. 1B  is a schematic representation of a system complying with an embodiment of the invention, 
         FIG. 2  is a flow chart illustrating the implementation of the invention according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1A  represents a server for implementing the method in accordance with an embodiment of the invention. 
     The server  100  may include a processor  101 , a network module  102 , a data storage space  103  and RAM (Random Access Memory) memory  104 . The server  100  corresponds in this example to physical equipment, i.e. a computer hardware device. The processor  101  may comprise one or more cores, or may correspond to multiple processors. The network module  102  provides the connection means to at least one communication network. Since the server  100  is intended to be integrated into a communication network, the technology used by the network module  102  may vary according to the technology used in the communication network. The network module may, for example, comprise an “Ethernet” socket and offer IP (Internet Protocol) connectivity to the server  100 . The network module  102  therefore allows the server  100  to receive and send (or transmit) messages via the communication network. The data storage space  103  may correspond to physical or virtual hard disks, accessible locally or via the network module  102 . The storage space  103  allows the server  100  to create, modify, manage databases, and therefore record data, e.g. messages, in a database. These databases may be shared with other servers, i.e. being created, managed, or accessible from other servers. 
     In order to simplify the description of the present invention, the reference  103  will be used hereafter as designating a database connected to the server  100 . This database  103  may therefore be local, i.e. included in the storage space of the server  100 , or remote, i.e. included in another server or plurality of servers. The server  100  may therefore record in the database  103  messages received via the network module  102 . The server  100  may also retrieve recorded messages in the database  103  and send these messages via the network module  102 . The server  100  may also record or retrieve lists of identifiers in the database  103 . The server  100 , via the processor  101  may thus determine whether an identifier of a message received via the network module  102  belongs to an identifier list. 
     According to the implementations, the server  100  may alternatively be implemented as a virtual machine of a virtualization server, or have its functions integrated into another server providing other applications or functions. 
       FIG. 1B  is a schematic representation of a system complying with an embodiment of the invention. This figure represents a first terminal  110  connected to a communication network  150  and a second terminal  120  connected to a communication network  160 . The communication network  160  is possibly the same as the communication network  150 . The server  100  is represented here as included in the communication network  160 . The server  100  may also be a physical device independent of the communication network  160  and connected to it. The server  100  may also have its functions and capabilities integrated into another server already providing other services for the communication network  160 . 
     These communication networks  150  and  160  are typically GSM/UMTS networks, the terminals  110  and  120  being mobile phones, tablets, smartphones, etc. 
     In this context of GSM/UMTS communication networks  150  and  160 , the identifiers associated with the terminals  110  and  120  are also termed phone numbers (or “numbers”). 
     The terminals  110  and  120  are therefore capable of establishing any type of communication as is known for GSM/UMTS communication networks. For example, the terminals  110  and  120  are capable of exchanging short message messages, also known as SMS (Short Message Service). Since a single SMS has a size limited to 160 characters (according to the coding), a message comprising a text with a length exceeding this limit may therefore be composed of multiple concatenated SMSs. 
     In the implementation of the present invention illustrated in  FIG. 1B , the server  100  is included in the communication network  160 . In an alternative embodiment, the server  100  may be included in the communication network  150  or in another communication network not represented in this  FIG. 1B . This will be particularly the case if the terminal  120  is in a “roaming” situation, i.e. it is not connected to its usual communication network. In an alternative embodiment, all the functions—or only certain functions—of the server  100  are integrated into a server providing other services. In particular, in one embodiment, the functions of the server  100 —or only certain functions—are performed by the terminal  120 . 
       FIG. 2  is a flow chart illustrating the implementation of the invention according to one embodiment. This figure describes various message exchanges according to an implementation of the method provided for filtering messages sent by the terminal  110  to the terminal  120 . This method of filtering can be used to provide the user of the terminal  120  with a “Do Not Disturb” or DND service. According to the embodiment illustrated in  FIG. 2 , the server  100  is compliant with the previously described server  100 . For the sake of simplicity in the description of  FIG. 2 , the terminals  110  and  120  and the server  100  will be considered as included in the same communication network, e.g. of the GSM/UMTS type, without this being in any way limiting. In an initial state, the operation of the terminals  110  and  120  is compliant with the conventional operation of GSM terminals. In particular, these terminals can exchange SMS short messages. A message sent by the terminal  110  will therefore be transmitted by the communication network and received by the terminal  120 , which will indicate the reception of this message by vibrating, ringing or displaying a notification, potentially bothering the user of the terminal  120 . The user of the terminal  120  who wishes to limit these disturbances may therefore activate a “Do Not Disturb” service, which will be provided by setting up the method of filtering described in this document. 
     According to one embodiment, the user of the terminal  120  wishing to use the “Do Not Disturb” service may have to install an application on their terminal  120  to use the service. The application will be installed according to the usual known process, e.g. by going to retrieve this application from an application store such as Google Play, the Apple App Store or the Windows Phone Store, to name just the main stores used today. Alternatively, the application will be pre-installed on the terminal  120  by the operator of the communication network or the manufacturer of the terminal  120 , or even incorporated directly into the OS (Operating System) of the terminal. The user of the terminal  120  may also go to retrieve the application on a site of a communication network operator. As will be described in detail farther on, one function of the application is in particular to activate or deactivate the “Do Not Disturb” service, said activation or deactivation being done by sending a message to the server  100 . This message may be of any type, in particular SMS or USSD (Unstructured Supplementary Service Data). More generally, the messages exchanged between the second terminal  120  and the server  100  may be of any type, e.g. USSD or data messages transmitted by an IP (Internet Protocol) technology. 
     According to a complementary embodiment, the user of the terminal  120  does not need to install or use any particular application and may activate the service by communicating with the server  100  by any method. The user may indeed send SMS or USSD messages directly without having to go through a particular application. The user may also access the service, i.e. activate it, deactivate it or configure it via a web interface. The server  100  may or may not host the web server allowing the configuration of the service. According to a particular embodiment, the installation of an application will be mandatory on the terminal  120 , the application being able to comprise authentication mechanisms for communicating securely with the server  100  providing the message filtering service. 
     Thus, in a first step  202 , the service for filtering messages to the terminal  120  is activated. In one embodiment, the activation of the service is triggered by the reception of a message  201  sent by the terminal  120 . The server  100  thus receives a message  201  sent by the second service activation terminal. According to an alternative embodiment, the message  201  may be sent by other equipment and comprises an identifier of the terminal  120 . The message  201  may comprise one or more instructions for requesting the activation of the filtering service. When activating the service for the terminal  120 , the server  100  retrieves in the database  103  one or more predetermined lists associated with the terminal  120 . These lists include identifiers and therefore can be used to customize the filtering of messages sent to the terminal  120  according to the identifier of the sender of the messages. Alternatively, lists may be included in the activation message received. Lists may also be retrieved on another remote server, e.g. a server operated by the provider of the “Do Not Disturb” service. 
     A first identifier list, a “green list” may thus be set up. This green list may be set up by the user of the terminal  120  or by the operator of the “Do Not Disturb” service. The point of this list is to define identifiers for which the delivery of the messages to the terminal  120  will be immediate. Indeed, if the server  100  determines that an identifier of the sender of a message to the terminal  120  belongs to the green list, then this message will be transmitted directly to the terminal  120  without executing the subsequent steps of the method of filtering. In other words, these messages from identifiers in the green list are not filtered. This green list therefore corresponds to emergency service identifiers (fire department, etc.) or identifiers added by the user of the terminal  120  according to their needs. The user of the terminal  120  thus keeps the possibility of adding identifiers for which filtering will not be performed even when the “Do Not Disturb” service is active. The part of the list corresponding to emergency service identifiers may be common to all the users of the “Do Not Disturb” service. 
     Another identifier list, a “gray list” may also be set up. This gray list may include “short number” or “premium rate” identifiers or more generally identifiers corresponding to services. This first identifier source for the gray list may be set up by the operator of the “Do Not Disturb” service by the user of the terminal  120 , or by the service operator and the user of the terminal  120 . A second identifier source for this list is the user of the terminal  120  who may add identifiers at their convenience. This list is intended to determine identifiers for which the method of filtering will be partially performed. As will be seen farther on in this description, the messages from these identifiers will be recorded by the server  100  in the database  103  without a message  207  being sent in return. These messages will only be delivered when the user of the terminal  120  deactivates the “Do Not Disturb” service. 
     The part of the gray list corresponding to “short number” or “premium rate” service identifiers may be common to all the users of the “Do Not Disturb” service. 
     One or more other identifier lists, “white lists”, may be defined. These white lists are a priori set up by the user of the terminal  120  and correspond to identifiers that the user of the terminal  120  wishes to prioritize. A different identifier NUM i may be associated with each white list i. 
     All these lists are recorded in the database  103  in association with the identifier NUM  120  of the terminal  120 . Possibly, all or part of these lists are common to one or more users of the “Do Not Disturb” service. 
     Thus, on reception of the message  201  activating the “Do Not Disturb” service by the server  100 , one or more predetermined lists, e.g. of the green, gray or white type, associated with the terminal  120  are obtained from the database  103 . The method of filtering allowing the provision of a “Do Not Disturb” service is then started and will apply to the messages subsequently sent to the terminal  120 . 
     This phase of activating the service may include a phase of modifying the routing of the messages to the terminal  120  within the communication network  160  so that following the activation of the service all the messages to this terminal  120  pass through the server  100 . Alternatively, as described hereafter, the step of determining whether the identifier of the sender field (hereafter, the sender identifier) of a message to the terminal  120  belongs to one of the predefined lists may be performed by other equipment of the communication network  160 , only the messages requesting particular processing (recording, for example) then passing through the server  100 . In other words, determining whether the sender identifier of a message belongs to the green list may be performed on a server other than the server  100 . 
     Following step  202 , the “Do Not Disturb” service is therefore active for the terminal  120 . According to one embodiment, a message  203  confirming the successful activation of the service is sent to the terminal  120 . 
     Step  206  corresponds to the reception by the server  100  of a message  205  sent by a terminal  110  to the terminal  120 , the identifier associated with the terminal  110  being NUM  110 . 
     Assuming that the verification of whether NUM  110  belongs to the green list associated with the terminal  120  has not been previously performed by another server, it will then be determined whether NUM  110  belongs to the green list. If this is the case, then, as seen previously, the message  205  will be transmitted directly to the terminal  120  without sending the second message  207 . 
     Likewise, if it is determined that NUM  110  belongs to the gray list associated with the terminal  120 , then, as seen previously, the message  205  will be recorded in the database  103  without sending the second message  207 . These messages sent by a terminal  110  the identifier of which belongs to a gray list and recorded in the database  103  will be sent to the terminal  120  on the deactivation of the service. 
     In other cases, the message  205  is recorded in the database  103 . The server  100  then determines whether NUM  110  belongs to a pre-defined list associated with the terminal  120 . If NUM  110  belongs to a list, e.g. a white list i, then the server sends a message  207  to the terminal  100 , the message  207  having as the sender identifier the NUM i associated with the white list. In other words, the message  207  includes a sender field that matches the identifier NUM i. 
     If NUM  110  does not belong to a predefined list of identifiers, then the server  100  sends a message  207  to the terminal  100 , the message  207  having as the sender identifier an identifier NUM d. In other words, the message  207  includes a sender field that matches the identifier NUM d. 
     The message  207  includes a text informing the user of the terminal  110  that their message  205  was not delivered to their correspondent since the latter has activated the “Do Not Disturb” service. The user of the terminal  110  is therefore informed that the user of the terminal  120  does not wish to be disturbed. However, if the user of the terminal  110  nevertheless wishes to disturb the user of the terminal  120  and force sending their message  205  to the terminal  120 , the method of the present invention allows this as described in detail below. The assessment of the urgency of the situation therefore rests both with the user of the terminal  120  via the definition of predefined lists, and with the user of the terminal  110  who will alone decide whether it is appropriate to disturb the user of the terminal  120  after receiving a message  207 . 
     If the user of the terminal  110  judges that their message  205  is not urgent and that they therefore do not wish to disturb the user of the terminal  120 , the user of the terminal  110  need perform no further action. Their message  205  is recorded in the database  103  and will be sent automatically by the server  100  to the terminal  120  when the “Do Not Disturb” service is deactivated. It should be noted that the “Do Not Disturb” service may be deactivated on request by the user of the terminal  120 , as will be seen, but also that the service may be deactivated automatically. For example, a maximum duration of operation of the “Do Not Disturb” service may be defined. This duration may be common to all users or selected by the user of the terminal  120  when activating the service, e.g. by indicating a maximum duration of operation of the service in the message  201  activating the service. 
     If on the contrary the user of the terminal  110  judges that the message  205  needs to be sent urgently to the terminal  120 , then the terminal  110  sends a message  210  to the server  100 . This message  210  is sent by responding to the message  207  received by the terminal  110 . In other words, the message  210  is sent to the sender identifier NUM i or NUM d of the message  207 . Messages intended for the identifiers NUM i associated with the white lists or intended for the identifier NUM d are therefore sent to the server  100 . 
     Step  211  corresponds to the reception by the server  100  of a message  210  to NUM j from NUM  110 . In other words, the recipient field of the message  210  includes an identifier NUM j. The server then determines whether NUM  110  belongs to a predefined list, a predefined list associated with an identifier NUM k. If NUM k and NUM j correspond, i.e. they match, then the server  100  retrieves in the database  103  a recorded message  212 , sent by the terminal  110  to the terminal  120 , and sends this message  212  to the terminal  120 . The message  212  corresponds to a message  205  previously recorded in the database  103 . 
     If NUM  110  does not belong to a predefined list, then the server  100  verifies that NUM j corresponds to NUM d, i.e. that NUM j matches NUM d. If this is the case, then the server  100  retrieves in the database  103  a recorded message  212 , a message sent by the terminal  110  to the terminal  120 , and sends this message  212  to the terminal  120 . 
     Otherwise, i.e. an identifier NUM j does not correspond to the identifier associated to with the list of identifiers to which NUM  110  belongs, or if NUM  110  does not belong to a list, to NUM d, then the message  210  is ignored by the server  100 . 
     This step of verifying the consistency between NUM j and an expected identifier prevents a user of a list associated with one identifier sending a message  210  to another identifier. In other words, assuming that the identifiers NUM i and NUM d correspond to premium rate numbers, this prevents a user sending a message  210  to a number different from the premium rate number that they should use. This is possible if this user does not respond to the message  207 —i.e. reuses the number of the sender of the message  207  as recipient—but edits a message  210  by choosing a recipient themselves. Without this verification, a user of a terminal  110  could choose the lesser rate premium rate number, weakening the effect of the method. 
     In another alternative embodiment, the step of verifying the agreement between NUM j and NUM k or NUM d respectively is not performed. Indeed, assuming that the charges for sending messages to the second and third identifier would be different, and in order to prevent a first user sending a fourth message  210  only to the less expensive identifier, it is useful to verify that the destination identifier of the fourth message  210  does correspond to the sender identifier of the second message  207 . In other words, it is useful to verify that the first user does respond to the second message  207  using the identifier contained in the sender field of the second message. However, assuming that the first user will respond to the second message  207 , and therefore that the message  210  will actually be sent to the correct identifier corresponding to the sender of the second message  207 , this verification step may be ignored. In other words, according to the security level sought, the step of verifying the matching of identifiers may not be performed. 
     In this case, after receiving the message  210 , the server  100  determines whether the identifier NUM j matches a known identifier, i.e. an identifier associated with a predefined list or NUM d. If so, the server then retrieves a recorded message in the database  103  which is intended for the second terminal  120  then sends this retrieved message to the second terminal  120 . If not, the message  210  is ignored. 
     A message  213  may be sent by the server  100  to the terminal  110  for confirming successful reception of the message  210 . Alternatively, the message  213  is sent to indicate to the user of the terminal  110  that a message  212  has actually been sent to the terminal  120 . 
     According to the embodiment of the method of the present invention, the message  212  sent to the terminal  120  may be retrieved in the database  103  in a different way. 
     According to one method, the message  212  recorded in the database  103  which is retrieved and sent to the terminal  120  corresponds to the last message sent by the terminal  110  to the terminal  120  to have been recorded in the database  103 . In other words, the to retrieved message is the last of the recorded messages, sent by the first terminal  100  to the second terminal  120 . This method thus allows an “unblocking” of the recorded messages on the “last in, first out” principle. Alternatively, the message  212  retrieved and sent may correspond on the contrary to the first message sent by the terminal  110  to the terminal  120  to have been recorded in the database  103 , according to the “first in, first out” principle. 
     According to another alternative method, the message  207  includes a reference for identifying the message  205  recorded in the database. The message  210  includes this same reference, which allows the server to retrieve in the database  103  the message  205  corresponding to this reference. The message  212  sent then corresponding to the message  205  previously recorded which has as a reference the reference included in the message  210 . A message  205  received by the server  100  is therefore recorded in the database  103  in association with a reference, this same reference being sent in the message  207  in return. The provision of this reference in a message  210  allows the message recorded in the database  103  to be retrieved and sent to the second terminal  120 . Assuming that multiple messages  205  are sent by the terminal  110  to the terminal  120 , this alternative method can therefore be used to select which of these multiple messages will be retrieved and sent following the reception by the server  100  of a message  210 . The selection being made by the provision in the message  210  of the reference corresponding to the message recorded in the database  103 , the reference received in a message  207 . 
     It should be noted that the message  212  retrieved in the database and sent to the terminal  120  is then deleted from the database  103 . 
     According to the embodiment, a message  214  is sent by the terminal  120  to the terminal  110  to indicate the successful reception of the message  212 . 
     Thus, when the “Do Not Disturb” service is active for a terminal  120 , any message  205  sent by a terminal  110  to the terminal  120 , the identifier of which is not included in a gray or green list associated with the terminal  120  will be recorded by the server  100  in a database  103 . The message  205  is therefore not delivered to the terminal  120  at this stage. A message  207  will be sent in return to the terminal  110 , the sender field of this message  207  will be dependent on whether the identifier of the terminal  110  belongs to a predefined list associated with the terminal  120 . The user of the terminal  110  has the possibility of responding to this message  207  by a message  210  to unblock the sending of a message  205  previously sent. Unblocking will be understood to mean retrieving in the database  103  a message, sent by the terminal  110  to the terminal  120  and previously recorded in the database  103  then this message being sent to the terminal  120 . According to the embodiment, the retrieved message is then deleted from the database  103 . 
     Step  221  corresponds to the deactivation by the user of the terminal  120  of the “Do Not Disturb” service. It should be noted that as seen previously, deactivation may be automatic, e.g. after expiration of a predefined time period. Other criteria for activation or automatic deactivation of the service are possible. For example, a synchronization with a diary application on the second terminal  120  may activate and terminate the service automatically at the start and end of a meeting. The activation or deactivation of the service may also be triggered by the position of a sensor on the terminal  120 , the face down position on a table corresponding, for example, to the automatic activation of the “Do Not Disturb” service. The user of the terminal  120  may also define hourly ranges for activating the service. Coupling with a geolocation application may also allow the service to be automatically activated or deactivated when the terminal is located in certain places, possibly adding hourly criteria thereto. In these cases, as for automatic deactivation following the expiration of a time period, the server  100  may automatically deactivate the service. In other cases, the server may need to receive a message  220  indicating the deactivation of the “Do Not Disturb” service for the terminal  120 . The server  100  thus receives a message  220  sent by the second terminal  120  requesting deactivation of the service. In both cases, the server  100  retrieves all the messages  222  recorded in the database  103  and intended for the terminal  120  and sends them to the terminal  120 . These messages  222  may then be deleted from the database  103 . 
     It should be noted that the messages  222 , just like the messages  212 , have a sender identifier corresponding to the original sender of the message, that is to say, for example, NUM  110  for a message  205  initially sent by the terminal  110 . 
     Following the deactivation of the service, any message sent to the terminal  120  will be delivered to it normally. Deactivation, following the example of the activation of the service, may include a step of modifying the routing of messages to the terminal  120 . 
     The method of filtering includes a step  216 , which could equally be executed when the “Do Not Disturb” service is active or not, this step  216  corresponding to the updating or configuration of one or more lists by the user of the terminal  120 . This updating of a predefined list associated with the terminal  120  may be done by sending messages  215 , including, for example, identifiers to be added to a list, the list being identified by a pre-established reference. The user of the terminal  120  may therefore customize and manage the lists. 
     According to one embodiment, the method of filtering previously described has the feature that the identifiers NUM i associated with the predefined lists or the identifier NUM d, used by default when sending the message  207  as sender, and accordingly used as a recipient identifier of the message  210  sent by the terminal  110 , correspond to premium rate numbers. Thus, after receiving a  207  type message, in addition to the need for the user to have to assess whether or not they really wish to disturb the user of the terminal  120 , and if so, take the time to send a message  210 , the user of the terminal  110  will have to decide whether they are willing to pay for this cost corresponding to the premium rate number. The user of the terminal  120  may thus set up a number white list corresponding to known user terminals, for which the premium rate will be low or even zero. Conversely, for numbers outside this list, or belonging to other lists, the premium rate will be higher. It should be noted that the premium rate associated with the identifier NUM d, applied by default for an identifier that does not belong to a list, is not necessarily the highest premium rate, the user of the terminal  120  being able to define a user list for which the premium rate is maximum. 
     According to one embodiment, all or part of the collected premium rate is paid to the service user, or to any other organization or entity, possibly defined by the user of the service. 
     According to one embodiment of the invention, in the case of a plurality of identifier lists, the same identifier or number may only belong to a single list. In an alternative embodiment, if an identifier has to belong to multiple lists, then one list would be considered by the server  100  as taking priority over the other lists. In terms of implementation, this may mean that the method of filtering described may proceed sequentially with the process of determining an identifier in a list if there are multiple lists, the priority lists being scanned first (e.g. first the green list, then the white lists, then the gray list, etc.). The sequence may be defined by the user of the service. 
     According to a complementary embodiment, the messages  207  and  210  include an indication of the identifier of the recipient of the message  205 . Indeed, in the case of sending a message to multiple users having activated the “Do Not Disturb” service, the server  100  may send back to the sender of the message  205  a different message  207  per recipient having activated the service, the different messages  207  being distinguished by information on the particular recipient. The user of the message  205  may then send a message  210  including a reference to the recipient number to only unblock this single message to this single recipient. It should be noted that as seen previously, the server  100  may then unblock either the first message to have been recorded in the database  103 , or the last, or a message identified by a particular reference. 
     Alternatively, according to another embodiment, a single message  207  is sent by the server  100  in response to a message  205  sent to a plurality of terminals in activated “Do Not Disturb” mode. A single message  210  is then sufficient to unblock the sending of the waiting message to the plurality of destination terminals. 
     According to an alternative embodiment, the various steps of the method are partly performed by the terminal  120 , the service taking the form of an application running on the terminal  120 . A server  100 , connected with terminal  120 —for example by an IP data connection—is used to execute some steps of the method. The messages  201 ,  203 ,  212 ,  215 ,  217 ,  220  and  222  are internal messages to the application running on the terminal to  120 . The terminal  120  running the application, when the “Do Not Disturb” mode is active, may not react to the reception of a message  205  in order not to disturb the user. The message  205  is recorded on the terminal  120 . The terminal  120  sends an instruction to the server  100  to send a message  207  to the terminal  110  indicating to it that the terminal  120  is in “Do Not Disturb” mode. The message  207  includes as previously a sender field corresponding to an identifier NUM i that is possibly premium rate. In case of reception of a message  210  by the server  100 , the latter sends an instruction to the terminal  120  to unblock the corresponding message  205 , i.e. the message is retrieved in the database  103  of the terminal and presented so as to give the illusion to the user of the terminal that it has only just been received. 
     According to an alternative embodiment, the method of filtering messages is applied to voice communications—or voice and video for a video conferencing communication—between the first and second terminal. More specifically, the method of filtering messages is applied to the filtering of messages corresponding to requests for establishing communications (e.g. voice or video) to the second terminal (in other words, voice or video calls to the second terminal  120 ). In this case,  FIG. 2  should be read as follows:
         the message  205  corresponds to a request for establishing communication sent by the terminal  110  to the terminal  120 . It may be a voice, voice and video, etc. communication.   step  206  corresponds to the interception by the server  100  of this request for establishing a communication with the terminal  120 . The information corresponding to this request is recorded in the database  103 .   according to one embodiment, a voice message may be broadcast by the server  100  to the terminal  110 , a message informing, for example, the user of the terminal  110  that the user of the terminal  120  does not wish to be disturbed. The broadcast message may be adapted according to whether the identifier of the terminal  110  belongs to a pre-defined list; alternatively or complementarily, the call may be redirected—directly or after broadcasting the voice message therefore—to a voicemail of the user of the terminal  120 ,   the message  207  corresponds to a message, e.g. an SMS, which is sent to the terminal  110  by the server  100 , a message sent with a sender field including an identifier NUM i dependent on whether the identifier of the terminal  110  belongs to a predefined list, as seen previously. This message informs the user of the terminal  110  of the fact that the user of the terminal  120  does not wish to be disturbed, but that it is possible to reach the user of the terminal  120  at the number corresponding to the identifier NUM i, this identifier possibly corresponding to a premium rate number.   if the user of the terminal  110  wishes to reach the user of the terminal  120 , they resend a message  210  requesting the establishment of communication (or a call) to the identifier NUM i, a call that will be received by the server  100 . The server  100  will then place the terminal  110  in communication with the terminal  120 . To do so, the server  100  will itself send a call to the terminal  120 . The call will be billed to the user of the terminal  110  according to the cost corresponding to the premium rate number NUM i.   When the user of the terminal  120  terminates the service (step  221 ), the information concerning the requests for establishing communications with the terminal  120  will be retrieved in the data base  103  and sent to the terminal  120 . In other words, on the deactivation of the “Do Not Disturb” service the terminal  120  will receive a log of the filtered calls. Alternatively, the terminal  120  may be sent updates by the server  100 —in real-time or delayed—of the filtered calls log.