Abstract:
A method and apparatus for determining a plurality of parameters indicative of performance of an analog telephone line is disclosed. The method includes sequentially performing a plurality of tests on the analog telephone line. The method further includes sequentially indicating results of the plurality of tests using a same set of visual indicators. In one embodiment, the performing the plurality of tests includes performing a second and a third sequential test upon detection of sequential activation of a test initiation input device. In another embodiment, the determining a plurality of parameters includes determining any one of loop current, ring voltage and ring trip energy of the analog telephone line.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to telephonic communications, and in particular to a method and system for evaluating an analog telephone line in order to assess its adequacy for use. 
       BACKGROUND OF THE INVENTION 
       [0002]    As new infrastructure configurations, new products and new vendors enter the telephonic communications market, it can become difficult for telephonic equipment providers to evaluate new products and service offerings for proper operation with their equipment. Namely, loop current, battery voltage, ring voltage and ring trip energy are elements of a telephonic system that are crucial to the integrity and functionality of the system. Battery voltage is the voltage that exists on a working telephone line. The battery voltage is present at all times on a working telephone line. Loop current is applied to a telephone line when the handset is picked up. Loop current provides the energy required for the telephone handset to operate and provides supervision that informs the telephone central office that the handset is ready to make a call or is answering a call. Ring voltage is the voltage existing on the telephone line when a call is being made to the telephone handset, prompting the handset to ring. Ring trip energy is the energy that must be absorbed during the transition from a call being placed to a call being connected. 
         [0003]    Battery voltage, loop current, ring voltage, and ring trip energy, however, cannot be measured directly with a conventional multimeter. Loop current and ring trip energy require a precision load to be placed across the telephone line while the measurement is being recorded. Ring voltage and ring trip energy require a device that can detect when ringing is occurring and take measurements at the proper time. In the case of ring voltage, the instrument must also take a series of measurements over time to determine the actual root mean square (RMS) value of the complex waveform. When measuring ring trip energy, an instrument must be able to measure the total dynamic power dissipated by the load in the transition from ringing to off hook, and the instrument must also be able to determine if the ring current exceeds the maximum allowable. These dynamic measurements can be captured by conventional test equipment, but the required equipment is bulky, expensive and requires a higher level of expertise to use. 
         [0004]    While it is possible to obtain analog line installation measurements and network configuration information from the carrier before installing certain telephonic equipment, carriers are typically reluctant to share this information, if it is even available. Further, the information may not always be up to date. Alternatively, equipment may simply be installed without regard to testing, upon which corrective steps can be taken in the event of failure or inoperation. Unfortunately, this requires replacement of damaged equipment, resulting in loss of money for an equipment provider to replace the damaged equipment, loss of time and money for customers while defective equipment is replaced and loss of time and money for partners of an equipment provider who must perform the replacement. 
         [0005]    In view of the above-described shortcomings, there is a need for a simplified and more efficient way to assess whether analog phone line operation parameters are within specification. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention advantageously provides a method and apparatus for determining a plurality of parameters indicative of performance of an analog telephone line. In one embodiment, the present invention provides a hand held device that uses an inexpensive microcontroller that is able to assess whether analog phone line parameters are within specification and convey such information through a simple display. In addition, an embodiment of the present invention provides a device that is portable, quick to setup and requires minimal training to use. 
         [0007]    In accordance with one aspect, the present invention provides a method for determining a plurality of parameters indicative of performance of an analog telephone line. The method includes sequentially performing a plurality of tests on the analog telephone line. The method further includes the capability to sequentially indicate the stored results of the plurality of tests using the same set of visual indicators. In one embodiment, performing the plurality of tests includes performing a second and a third sequential test upon detection of sequential activation of a test initiation input device. In another embodiment, determining a plurality of parameters includes determining any one of loop current, ring voltage and ring trip energy of the analog telephone line. 
         [0008]    In accordance with another aspect, the present invention provides an apparatus for determining a plurality of parameters indicative of performance of an analog telephone line. A probe is couplable to the analog telephone line. A set of indicators provides a visual indication of each value corresponding to the plurality of parameters. A processor such as a microcontroller is configured to sequentially perform a plurality of tests on the analog telephone line via the probe and uses the same set of indicators to provide a visual indication of results of each of the plurality of tests. 
         [0009]    In accordance with still another aspect, the present invention provides an apparatus for determining a plurality of parameters indicative of performance of an analog telephone line. The apparatus includes a set of test result indicators and a probe couplable to the analog telephone line. The apparatus further includes a test activation input device, a load switch and a power supply. A microcontroller is configured to sequentially perform a plurality of tests on the analog telephone line via the probe and to cause the set of test result indicator lights to provide a visual indication of results of each of the plurality of tests. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    A more complete understanding of the present invention, and the attendant advantages and features thereof, is more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
           [0011]      FIG. 1  is a top view of a device constructed in accordance with the principles of the present invention; 
           [0012]      FIG. 2  is a block diagram showing an exemplary electrical circuit of the device of  FIG. 1 , in accordance with one embodiment of the present invention; 
           [0013]      FIG. 3  is a schematic diagram showing an exemplary embodiment of the device of  FIG. 2 , constructed in accordance with the present invention; and 
           [0014]      FIGS. 4 and 5  are a flow chart showing a measurement process in accordance with one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    Referring now to the drawing figures in which like reference designators refer to like elements, there is shown in  FIG. 1  a device  100  constructed in accordance with one embodiment of the present invention. Device  100  is a handheld device having a housing  102  constructed of a common semi-synthetic polymerization product such as plastic. The housing  102  includes a variety of text imprinted on it, so as to indicate the functions of the various features of the device  100 . Device  100  includes a button  104  for activating various functions of the device  100 , an analog telephone line jack  106  that serves as a probe into which the analog telephone line being analyzed is inserted, and an on/off switch  108  for turning the device  100  on or off. The button  104  protrudes through the housing  102 . The analog telephone line jack  106  can accept RJ-45 and RJ-11 telephone line plugs but can be arranged with other jacks as may be needed to couple the probe to different physical phone line configurations. The device  100  also includes a status Light Emitting Diode (LED)  110  for indicating which performance parameter is being analyzed and a set of indicators  112 , such as LEDs, for indicating the magnitude of each performance parameter. An LED  114  indicates the status of the battery of the device  100 . 
         [0016]    Using the device  100 , a user can test various performance parameters of an analog telephone line inserted into the jack  106 . The performance parameters include Central Office (CO) battery, or telephone line voltage, loop current, ring voltage, and ring trip energy. The device  100  uses the LED  114  to indicate whether the battery of the device  100  has sufficient charge to power the device  100 . By pressing the button  104 , the user indicates which performance parameter is being tested by the device  100 . LED  110  indicates, by the form in which it is illuminated (i.e., pulsing, rate of pulse, continuous illumination), which performance parameter is being tested by the device  100 . Further, the set of indicators  112  indicate the results of each performance parameter tested by the device  100 . 
         [0017]      FIG. 2  is a block diagram  200  showing the main components of the device  100  in accordance with one embodiment of the present invention.  FIG. 2  shows that the device  100  includes a test activation input device  204 , shown as a button  104  in  FIG. 1 . Other embodiments of a test activation input device  204  include an electro-conductive sensor or a data input port. Device  100  also includes test results indicators  202 , shown as LED indicators  112  in  FIG. 1 . Other embodiments of test results indicators  202  include a Liquid Crystal Display (LCD), an audio output device and a data output port. The device  100  also includes a power supply  210  that can be a nine volt battery or any other portable power supply module. 
         [0018]    The device  100  includes a microcontroller  206  or any other suitable processing unit that can perform and/or control the functions described herein. The microcontroller  206  manages the components of the device  100  and performs the calculations necessary to evaluate the performance parameters of the analog telephone line being tested. The test results indicators  202 , the test activation input device  204  and the power supply  210  are all electrically connected to the microcontroller  206 . 
         [0019]    Also connected to the microcontroller  206  is a load switch  208 , that is used to place a load onto the analog telephone line being tested, as explained in greater detail below. The load switch  208  is connected to the test load  212  that includes a filter  214  for eliminating extraneous signal information when evaluating the performance parameters of the analog telephone line being tested.  FIG. 2  also includes a rectifier  216  connected to the test load  212  and a probe  218 . The probe  218 , shown as jack  106  in  FIG. 1 , connects to the analog telephone line. The rectifier  216  rectifies the signal from the analog telephone line such that the probe  218  can be connected to the telephone line without regard to polarity. The microcontroller  206  contains an analogue to digital converter (ADC), used to measure the input from the rectifier  216  after the signal is scaled by a series of resistors. 
         [0020]      FIG. 3  is an exemplary schematic diagram for a circuit  300  for the device  100 , constructed in accordance with one embodiment of the present invention. Reference is also made to Table 1. Table 1 provides an exemplary list of components suitable to implement the circuit  100 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Component 
                   
               
               
                   
                 Reference 
                 Component Description 
               
               
                   
                   
               
             
             
               
                   
                 C1 
                 0.1 μF 50 V 
               
               
                   
                 C2 
                 680 pF 600 V 
               
               
                   
                 C3 
                 0.33 μF 15 V 
               
               
                   
                 C4 
                 0.01 μF 15 V 
               
               
                   
                 D1, D4 
                 GREEN LED 
               
               
                   
                 D2, D6 
                 RED LED 
               
               
                   
                 D3, D5 
                 YELLOW LED 
               
               
                   
                 D7–D10 
                 1N4005 
               
               
                   
                 D11 
                 1N5818 
               
               
                   
                 F1 
                 0.125 Amp Picofuse 
               
               
                   
                 F2 
                 1.0 Amp Picofuse 
               
               
                   
                 R1–R8 
                 1 kΩ 1%, ½ Watt 
               
               
                   
                 R9, R10, R13 
                 100 Ω 5%, ¼ Watt 
               
               
                   
                 R11 
                 10.0 kΩ 1%, ¼ Watt 
               
               
                   
                 R12 
                 1.00 mΩ 1%, ¼ Watt 
               
               
                   
                 R14 
                 4.7 kΩ 5%, ¼ Watt 
               
               
                   
                 R15–R17 
                 75 Ω 5%, ¼ Watt 
               
               
                   
                 U1 
                 PIC12F675 8-bit CMOS Microcontroller 
               
               
                   
                 U2–U3 
                 IRFN320 
               
               
                   
                 U4 
                 78L05 5-volt Voltage Regulator 
               
               
                   
                   
               
             
          
         
       
     
         [0021]    The schematic diagram of  FIG. 3  corresponds to the block diagram of  FIG. 2 . LEDs D 1 , D 2 , D 3 , D 4 , D 5  and D 6  in combination with resistors R 15 , R 16  and R 17  correspond to test results indicators  202  of  FIG. 2 , that are used, among other things, to indicate the results of the performance parameters being tested. LEDs D 1 -D 6  can be a combination of colored LEDs, such as red, green or yellow LEDs where green indicates passage, yellow indicates a slight out of tolerance condition and red indicates failure. Microcontroller U 1  corresponds to microcontroller  206  that manages the components of the device  100  and performs the calculations necessary to evaluate the performance parameters of the analog telephone line being tested. Microcontroller U 1  also performs analog to digital conversion of signals. The push button module consists of resistors R 13  and R 14 , capacitor C 4 , and grounded push button S 2  that corresponds to test activation input device  204 . 
         [0022]    Circuit  300  further includes a power supply module  210  having a voltage regulator U 4 , capacitors C 1 , C 3 , diode D 11 , on-off switch S 1  (corresponding to on/off switch  108  of  FIG. 1 ), fuse F 1  (that can be a picofuse of 0.125) and a nine volt power supply. The power supply module corresponds to power supply  210  of  FIG. 2 . Circuit  300  includes a load switch module having integrated circuits U 2 , U 3  (which can be transistors in 4-pin dip packages), that serve as switches, and damping resistors R 9 -R 10  to prevent oscillation of the paralleled devices. The load switch module corresponds to load switch  208  of  FIG. 2  that is used to switch a load onto the analog telephone line being tested. Test load  212  includes resistors R 1 -R 8 . The load  212  is used to load the analog telephone line being tested. Capacitor C 2  corresponds to filter  214  of  FIG. 2  that is used to filter out high frequency noise components from signals on the analog telephone line being tested. Resistors R 11  and R 12  can be used to scale down the input voltage provided to the microcontroller  206  from 500 to 5 volts. 
         [0023]    A full wave rectifier bridge having diodes D 7 -D 10  is connected to the test probes  218  via a fuse F 2  (that can be a picofuse 1.0 Amps). The full wave rectifier bridge corresponds to rectifier  216  of  FIG. 2  that rectifies the signal from the analog telephone line such that the probes (corresponding to probes  218  of  FIG. 2 ) can be connected to the telephone line without regard to polarity. 
         [0024]      FIGS. 4 and 5  show a flow chart of the operational measurement process of the device of  FIGS. 1-3 . To operate the device  100 , the user begins in step by turning on the device  100  using the on-off switch  108  (step S 400 ). At step S 402  the status of the battery of device  100  is evaluated by taking a voltage measurement (circuitry not shown in  FIGS. 2-3 ). The result is displayed as follows (step S 404 ). If the battery of the device  100  is sufficient to power the device  100 , LED  110  pulses in a green color. LED  114  is red and only comes on if there is sufficient power in the battery to illuminate LED  114  and the device supply voltage is out of tolerance. Obviously, if the battery is dead, no LEDs light. If the battery is good and power supply output is within tolerance, LED  114  will not light. Accordingly, if the battery of the device  100  is not sufficient to power the device  100 , the LED  114  either is not illuminated or illuminates in a red color and step S 500  ( FIG. 5 ) is performed, for example, by the user. Of note, the steps shown in  FIG. 5  (steps S 500 -S 512 ) are steps that can be performed by a user to aid his/her usage of the device and facilitate further testing and/or repair of the phone line under test. 
         [0025]    In step S 406 , the user proceeds to plug the analog telephone line being analyzed into the analog telephone line jack  106 . To indicate that the Central Office (CO) battery, or telephone line voltage, is being tested the LED  110  pulses in step S 408  and the line voltage test is performed by the microcontroller  206  by measuring the voltage present across probe  218 . The result is displayed using test results indicators  202  (see  FIG. 2 ). 
         [0026]    If the telephone line voltage operates within established parameters (step S 4120 , the middle green LED of LED indicators  112 , in the range labeled “Normal” is illuminated if the measured voltage is near the middle of the acceptable range or one of the two yellow LEDs are illuminated if the voltage is still considered normal, but is not quite centered. For example, if the telephone line voltage measures between 42-52 volts, the line is deemed to be operating within the center of the established range and the green LED illuminated. If the line voltage is measured at 36-42 volts, or 52-56.5 volts, voltage is still considered normal, but one of the two yellow LEDs is illuminated (one for the low side of normal and the other for the high side of normal). If the telephone line voltage does not operate within established parameters, the first or last LED of LED indicators  112 , labeled “Low” or “High,” is illuminated depending on whether the voltage was less than 36 volts or greater than 56.5 volts. Step S 502  ( FIG. 5 ) is performed, for example, by the user. 
         [0027]    If the line voltage is normal, the user presses the button  104  to activate the next phase of testing by microcontroller  206  (step S 412 ), namely loop current testing, and the line voltage test result data is stored in memory of the device  100 . To indicate that loop current is being tested the LED  110  is flashed rapidly (step S 414 ). In step S 416 , the device  100  subsequently tests and displays the loop current test result. The device  100  simulates a set going off-hook by placing a load across the analog telephone line, taking the analog telephone line off-hook for a predetermined period of time (250 ms, for example), switching the test load  212  onto the line and taking a current measurement from the analog telephone line. Also in step S 416 , the microcontroller  206  stores the information garnered from testing the loop current. 
         [0028]    If the loop current operates within established parameters (step S 418 ), the middle green LED of LED indicators  112 , in the range labeled “Normal,” is illuminated, thereby indicating that the measured current is near the middle of the acceptable range. If one of the two yellow LEDs is illuminated, the current is still considered normal, but is not quite centered. For example, if the loop current measures between 25-35 milliamps, the line is deemed to be operating within the center of the established range and the green LED is illuminated. If the loop current is measured at 20-25 milliamps, or 35-60 milliamps, loop current is still considered normal, but one of the two yellow LEDs is illuminated (one for the low side of normal and the other for the high side of normal). If the loop current does not operate within established parameters, the first or last LED of LED indicators  112 , labeled “Low” or “High,” is illuminated depending on whether the current was less than 20 milliamps or greater than 60 milliamps. In that case, step S 504  ( FIG. 5 ) is performed, for example, by the user. 
         [0029]    If the loop current is normal, the user presses the button  104  to activate the next phase of testing by microcontroller  206  (step S 420 ), namely ring voltage testing. To indicate that ring voltage is being tested the LED  110  is flashed slowly (step S 422 ). Subsequently, in step S 424 , a telephone call is placed to the line being tested by either the user of device  100  or a third party. In step  426 , the microcontroller  206  tests the ring voltage by detecting a ring voltage that is higher voltage than normal. Subsequently, a voltage reading is taken from the analog telephone line for a predetermined period of time (250 ms, for example) after detecting the ring voltage. In one embodiment, the microcontroller  206  determines whether the ring voltage is balanced or unbalanced on a first ring and measures the RMS value of the voltage on the second ring. Also in step S 426 , the microcontroller  206  stores the information garnered from testing the ring voltage and the result is displayed. 
         [0030]    If the ring voltage is within established parameters, the middle green LED of LED indicators  112 , in the range labeled “Normal” is illuminated, thereby indicating that the measured voltage is near the middle of the acceptable range. If one of the two yellow LEDs is illuminated, the voltage is still considered normal, but is not quite centered. For example, if the ring voltage measures between 75 and 95 volts, the line is deemed to be operating within the center of the established range and the green LED illuminated. If the ring voltage is measured at 65-75 volts, or 95 to 104 volts, ring voltage is still considered normal, but one of the two yellow LEDs is illuminated (one for the low side of normal and the other for the high side of normal). If the ring test did not complete (step S 428 ), the process continues at step S 506  ( FIG. 5 ). If the ring test completes, but the ring voltage does test as operating within established parameters (step S 430 ), the first or last LED of LED indicators  112 , labeled “Low” or “High,” is illuminated depending on whether the ring voltage was less than 65 volts or greater than 104 volts and step S 504  ( FIG. 5 ) is performed, for example, by the user. 
         [0031]    In step S 432 , the user presses the button  104  to activate the next phase of testing by microcontroller  206 . To indicate that ring trip energy is being tested the LED  110  is illuminated continuously and is steadily on (step S 434 ). In step S 436 , the ring trip energy test results are displayed. The ring trip energy is determined by taking the analog telephone line off-hook for a predetermined period of time (1 second, for example), measuring the ring trip energy and then placing the analog telephone line back on-hook. The microcontroller  206  takes the analog telephone line off-hook by switching the load  212  onto the line and places the analog telephone on-hook by removing the load  212 . Note this step terminates the incoming test call. Also in step S 436 , the microcontroller  206  stores the information garnered from testing the ring trip energy 
         [0032]    If the ring trip energy is within established parameters (step S 438 ), the middle green LED of LED indicators  112 , in the range labeled “Normal,” is illuminated, thereby indicating that the measured trip energy is near the middle of the acceptable range. If one of the two yellow LEDs is illuminated, the trip energy is still considered normal, but is not quite centered. For example, if the trip energy measures between 0.5-1.0 Joule, the line is deemed to be operating within the center of the established range and the green LED illuminated. If the trip energy is measured at 0.25-0.5 Joules, or 1.0-2.0 Joules, trip energy is still considered normal, but one of the two yellow LEDs is illuminated (one for the low side of normal and the other for the high side of normal). If the ring trip energy is measured at less than 0.25 Joules, this is not considered problematic. If the trip energy does not operate within established parameters, the last LED of LED indicators  112 , labeled “High,” is illuminated, thereby indicating that the trip energy was greater than 2.0 Joules. In this aspect of testing, the test results for the power component of the trip energy are indicated by which color LED indicator is illuminated. The present invention also measures the current component of the ring trip energy. If, during testing the ring trip energy, the current component exceeds a predetermined value, the LED indicator used to indicate the overall ring trip energy power value is set to flash. The predetermined current value can be based on, for example, the Telcordia Technologies GR-1089 standard. In the event of failure, step S 508  ( FIG. 5 ) is performed, for example, by the user. 
         [0033]    Once testing is complete, the user can review the testing results on test results indicators  204  (step S 440 ). This is done by activating the test activation input device  204 , e.g., pressing the button  104 , for a predetermined period of time, such as less than one second. The first activation (step S 442 ) causes the microcontroller  206  to present the results of the first test, e.g., the CO battery test (S 444 ). The repeated activation of the button  104  causes microcontroller  206  to step through the stored test results. The test whose results is being displayed is indicated by the status LED  110 , with the results of the test being shown on LED indicators  112 . The user can repeatedly step through the tests and results by pressing the button  104  for less than the reset time. As is described below, holding the button  104  for more than the reset time, e.g., 1 second, erases all stored values and returns the device to the ready to test state, e.g., step S 406 . 
         [0034]      FIG. 5  is a flow chart continuing the flow chart of  FIG. 4 , in accordance with one embodiment of the present invention. Step S 500  flows from a failed battery test result (step S 404  in  FIG. 4 ). In step S 500 , the user turns off the device  100  and checks and/or changes the device battery. Step S 502  flows from a failed line voltage test (step S 410  in  FIG. 4 .) In step S 502 , the user verifies all connections to jack  106 . Step S 504  flows from a failed loop current test (step S 418  in  FIG. 4 ), a failed ring voltage test (step S 430  in  FIG. 4 ) or where the user wishes to reset the device  100  (step S 440  in  FIG. 4 ). In step S 504 , the user presses and holds the button  104  to erase all values stored by the device  100  for the predetermined time period, e.g., greater than 1 second. 
         [0035]    Step S 506  flows when the ring test does not complete (step S 428  in  FIG. 4 ). In this case, the user verifies the telephone number corresponding to the jack the device  100  is plugged into and verifies that the line is configured to accept calls. 
         [0036]    Step S 508  flows from a failed ring trip energy test (step S 438  in  FIG. 4 ). In step S 508 , corrective action must be taken on the line under test. 
         [0037]    In the case of steps S 500 - 506 , if the failure of the corresponding test is the first failure, then, in step S 508 , the user retests. If the test fails again (step S 510 ) technical support is contacted (step S 512 ). 
         [0038]    In one embodiment of the present invention, the device  100  includes a sleep function wherein if the device is not in use for a predetermined period of time (such as 4.5 minutes), the microcontroller  206  turns off the LEDs of circuit  300  so as to conserve battery power. The sleep function can be initiated in the middle of a testing scenario. If the user decides to continue the testing scenario after the sleep function has initiated, the user can press button  104  to wake up the device  100  and continue the testing scenario from where he left off. After being woken up, the device  100  continues to possess in memory any information stored during the testing of performance parameters of the analog telephone line. 
         [0039]    Of note, although the tests are presented in a specific sequence in  FIGS. 4 and 5 , the present invention is not limited to such. The tests can be programmed to be performed in any order. Further, although the flow shown in  FIGS. 4 and 5  shows that the results of failed tests are not stored, the present invention is not limited to such. The results of failed tests can be stored for subsequent presentation/display to the user in accordance with steps S 440 -S 448 . 
         [0040]    When and if telephone standards change over time, it should be noted that the computer program can be modified to incorporate new values of the thresholds that determine when the LEDs D 1 -D 6  of  FIG. 3  are illuminated. 
         [0041]    Advantageously, the present invention provides a device that sequentially performs a group of tests on an analog telephone line and presents the results using the same set of visual indicators. In other words, a simple set of visual indicators, such as a group of LEDs, is used to display the results of each of the sequentially performed tests. 
         [0042]    The present invention can be realized in hardware, software, or a combination of hardware and software. An implementation of the method and apparatus of the present invention can be realized in a centralized fashion in one apparatus, or in a distributed fashion where different elements are spread across several interconnected apparatuses. Any kind of apparatus adapted for carrying out the methods described herein is suited to perform the functions described herein. 
         [0043]    A typical combination of hardware and software could be an apparatus having one or more processing elements and a computer program stored on a storage medium that, when loaded and executed, controls the components within the apparatus such that it carries out the methods described herein. The present invention can also be embedded in a computer program product, that comprises all the features enabling the implementation of the methods described herein, and when loaded in a device is able to carry out these methods. Storage medium refers to any volatile or non-volatile storage device. 
         [0044]    Computer program or application in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following a) conversion to another language, code or notation; b) reproduction in a different material form. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. Significantly, this invention can be embodied in other specific forms without departing from the spirit or essential attributes thereof, and accordingly, reference should be had to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.