Abstract:
A transponder of an interrogator and toll highway system has a non-electronically activated switch for a first state in which the transponder is in an “active” mode and a second state in which the transponder to be in an “inactive” mode. A non-electronic hanging device hangs the transponder in a vehicle for receiving interrogating signals and a non-electronic activator causes the switch to be in the first state only when the transponder is placed within the hanging device, and to be in an “inactive” mode when the transponder is not placed within the hanging device.

Description:
FIELD OF THE INVENTION 
     The present invention relates in general to means for enabling electronic payment on toll highways. More particularly, the present invention relates to means by which the driver can easily switch his toll transponder installed in his car between an “active” and “non-active” mode. 
     BACKGROUND OF THE INVENTION 
     It has become common to electronically monitor and charge vehicles entering or moving on toll highways by means of an interrogator and transponder. The interrogator is a transmitter/receiver device owned by the highway operator that communicates with transponders that are installed within the vehicles. One or more of such interrogators are installed at the entrance or at specific locations along sections of the highway. Only upon receipt of the interrogation signal, the vehicle transponder responds by transmitting the identity of the car (or any other unique signal enabling the identification of the car) to the interrogator. Upon receipt and processing of the transponder signal, the highway operator can charge the car owner for using the highway. 
     The interrogators and transponders usually operate by means of electromagnetic signals, but the present invention is not limited to any type of communication means, for example, optical, ultrasonic, etc. Most commonly, the interrogators and transponders operate by means of RF signals, and therefore the transponder is sometimes referred to as “RF ID”. Furthermore, there have been developed specific protocol standards for such interrogator-transponders communication, for example ASTM V6. 
     Generally, the vehicle transponder is in a form of an electronic card or in a form of a small circuit which is mounted within a closed, sometimes molded casing. The transponder is generally positioned by the driver at the internal side of the front vehicle window. 
     Generally, the transponders operate in an “always active” mode, i.e., there is no switch for turning them OFF. In order to save energy of the transponder battery, the transponder is designed to stay in “standby” mode during most of the time, and they switch to “transmit” mode only upon receipt of an interrogation signal. During the “standby” mode, the energy consumption is minimal. When the battery becomes weak or empty, the driver either replaces the battery or the whole transponder unit with the battery. 
     In some locations in the US regulations have been effected which allow drivers who carry passengers above a specific number to use dedicated lanes (HOV—High Occupancy Vehicle). Recently, in some locations in the US regulations have been effected which allow drivers who carry passengers under specific number to use said same dedicated lanes by paying toll. Such a manner of using the toll lanes requires the driver to switch his transponder between an “active” mode (when the number of passengers in the vehicle is below the limit, and he has to pay for using the lane) and a “non-active” mode (when the number of passengers is above that limit, and he does not to pay for using the lane. 
     As said, the conventional transponders operate in an “always active” mode, and they are not provided with a switch for its deactivation. One possible way which has been proposed for enabling a driver to deactivate the transponder is to use masking bag. More particularly, it has been proposed to provide each driver with a masking bag made of metal. When the driver wishes to deactivate the transponder, he is required to detach the transponder from its location on the window, and to put it in the masking bag. The masking bag masks and prevents electromagnetic signals from the interrogator to reach the transponder, or signals leaving the transponder to reach the interrogator. However, such an approach is not safe, as it requires the driver to perform actions that divert his attention from the highway. 
     Another approach that has been proposed is to provide within the transponder a simple ON-OFF switch accessible to the driver, that will be turned ON or OFF by the driver according to necessities. Although this option is possible, it also not safe, as it requires a significant attention by the driver. The status of the switch, which has to be relatively small, cannot be easily observed by the driver. Also, the location of the transponder may make it hard for the driver to determine the status of the switch. These size and location limitations, in addition to the safety issue, can make confusion to the driver, such that he might pay when he does not have to, or might violate the toll regulations by not payment. 
     As shown, both of the above two proposed arrangements are not convenient for the driver, and are not safe. 
     It is therefore an object of the present invention to provide an arrangement that will enable the driver to easily switch the status of the transponder between the “active” and “non active” modes, and to enable him to easily and accurately determine in what mode the transponder is. 
     It is a further object of the invention to enable said switching and status determination in a most convenience, and safety manner. 
     Other objects and advantages of the present invention will become apparent as the description proceeds. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a transponder system for use in conjunction with an interrogator of a toll highway, which comprises: (a) a transponder having two modes: (a.1) an “active” mode during which the transponder is mostly in standby, while it sends an identification signal upon receipt of an interrogator signal; and (a.2) an “inactive” mode during which the transponder is inactive; (b) a switch within the transponder having two states, a first state in which it causes the transponder to be in said “active” mode, and a second state in which it causes the transponder to be in said “inactive” mode; (c) a hanging device for enabling placement of the transponder in it, said hanging device being attached to a part of the vehicle where the transponder, when placed, is capable of receiving interrogating signals coming from a proximate interrogator; and (d) an activator at said hanging device for causing said switch to be in said first state only when the transponder is placed within the hanging device, and to be in an “inactive” state when the transponder is not placed within the hanging device. 
     Preferably, the transponder is an electronic card located within a closed casing. 
     Preferably, the switch is a magnetic switch or a reed switch located within the transponder, and wherein the activator is a magnet or made from a ferromagnetic material. 
     Alternatively, the switch is an optical switch located within the transponder, and wherein the activator is an element made from an opaque material which is placed at the hanging device at a location in which it interrupts the light passage at the switch when the interrogator is placed within the hanging device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the Drawings: 
         FIG. 1  shows a transponder for use in toll highways, with its hanging device, according to the prior art; 
         FIG. 2  is a block diagram generally illustrating the system of the present invention; and 
         FIG. 3  shows a transponder for use in toll highways, with its hanging device, according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As said, an object of the present invention is to provide an arrangement that will enable the driver to easily switch the status of the transponder between “active” and “non active” modes, and to enable him to easily and accurately determine in what mode the transponder is. Another object is to enable said switching and status determination in a most convenient and safe manner. 
       FIG. 1  shows a typical transponder  1  with its hanging device  2 . The transponder is generally attached to the internal surface of the front vehicle window, or to a location close to the window by means of some attachment device. For example, the device may be attached to the window by means of a hanging device  2 . The hanging device  2  generally has a sticker (not shown) at its rear surface, and hangers  3   a  and  3   b  at the front. The hanging device is generally attached to the front window at a location which at most minimally obstructs the view of the driver, for example, behind the front mirror. The transponder has at its back a corresponding cylindrical arrangement  4  (not shown) for engagement with said hangers  3   a  and  3   b.    
       FIG. 2  is a block diagram illustrating a toll system according to the present invention. The interrogator  30  communicates with a transponder  101  located within the vehicle  100 , and which is attached to a portion of the vehicle, for example to its front window by means of a device  102  which will be referred herein as a “hanging device”. According to the present invention the transponder  101  comprises a switch  103 . The switch  103  is designed to activate or deactivate the transponder. The state of the switch itself is controlled by means of a switch activator  104  located at the hanging device  102 . The switch activator operates in such a manner that when the transponder engages with the hanging device  102 , the activator  104  causes switch  103  of the transponder to activate the transponder, and when the transponder  101  is detached from the hanging device, the switch  103  deactivates the transponder. More particularly, the act of the engagement of the transponder to the hanging device causes the activation of the transponder  101 , As long as the transponder remains attached to the hanging device, it is active. However, when the transponder is detached from the hanging device it is deactivated. In other words, the act of the detachment of the transponder from the hanging device causes the deactivation of the transponder  101 . 
     According to the present invention the switch  103  which is generally positioned within the transponder and the activator  104  are adapted to operate together. For example, the switch may be a magnetic switch, and in that case the activator is a magnet or it is made from a ferromagnetic device. In that case the switch  103  is turned ON by sensing the proximity of the activator. In another embodiment, the switch  103  is a reed switch, and the activator is a magnet or it is made from a ferromagnetic device. A reed switch is an element known in the art which is capable of sensing proximity of a magnet or a ferromagnetic material. In a third embodiment, switch  103  is an optical switch which comprises a light emitting and light-sensitive elements directed one to the other. As long as the light passage between the two is maintained, switch  103  is OFF. When the light passage between the two is blocked, the switch turns ON. According to the said third embodiment, the activator  104  is a small opaque element that when the transponder is attached to the hanging device enters to within the light passage and blocks it, therefore turning the switch ON (and activating the transponder). 
       FIG. 3  shows a transponder  1  and a hanging device  102  according to an embodiment of the present invention. As before, the transponder is attached to the internal surface of the front vehicle window, or to a location close to the window by means of the hanging device  102 . The hanging device  102  has a sticker (not shown) at its rear surface, and hangers  103   a  and  103   b  at the front. The hanging device  102  is generally attached to the front window at a location which at most minimally obstructs the view of the driver, for example, behind the front mirror. The transponder  101  has at its back a corresponding cylindrical arrangement  4  for engagement with said hangers  103   a  and  103   b . The transponder further comprises within its casing a magnetic switch or a reed switch  106  for activating or deactivating the transponder, and the hanger further comprises a small magnet  107 . When the transponder is positioned to within the hanging device, switch  106  senses the proximity of the magnet  107 , and turns ON, therefore activating the transponder. When the transponder  101  is removed from its place within the hanging device  102 , the switch  106  no longer senses the proximity of magnet  107 , and therefore it turns OFF (i.e., it deactivates the transponder). 
     As shown, the activation of the device is performed by merely putting the transponder in its place within the hanging device  102 . The deactivation of the transponder takes place by merely removing the transponder from its place within the hanging device  102 . Therefore, when the driver wishes transponder to operate normally, he merely has to ensure that it is in its place within the hanging device. When he wishes to deactivate the transponder, for example when he carries a number of passengers above the limit, he has just to remove the device from its place, or to ensure that it is not in its place within the hanging device. 
     In the case when an optical switch is used within transponder  101 , the hanging device has to be designed to include a blocking, opaque element that will interrupt the passage of light when the transponder is put in its place within the hanging device  102 . 
     While some embodiments of the invention have been described by way of illustration, it will be apparent that the invention can be carried into practice with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the scope of persons skilled in the art, without departing from the spirit of the invention or exceeding the scope of the claims.