Abstract:
Systems and methods utilize cradle contacts for completing diagnostic tests of rechargeable devices, such as cordless telephones. A cordless telephone handset or base is placed into a test fixture. Once the handset or base is cradled, diagnostic message signals are transmitted through cradle contacts in the test fixture and handset/base. The message signals may be made up of ASK signals. The beginning and end of each test may be identified by a code or codes embedded in a message signal. The use of cradle contacts to complete diagnostic tests alleviates problems associated with use of internal test access ports to carry out such tests.

Description:
BACKGROUND OF THE INVENTION 
     Most people who use cordless telephones are familiar with the need to recharge the battery contained within the handset. A visual inspection of most cordless telephone handsets usually reveals the presence of electrical contacts embedded in the handset. When the handset is placed into the base of a cordless telephone, the contacts form a circuit with matching contacts embedded in the base. This circuit connection is used to recharge the battery contained in the handset using a power source routed through the base. These contacts are referred to as “cradle contacts.” The recharging of the handset necessarily requires an electrical current, referred to as a charging signal, to flow through the matching contacts. 
     During the manufacturing process both the base and handset must be tested to insure they are working properly. Additionally, handsets/bases must be tested when they are returned for servicing. Typically, once a handset has been assembled it can only be tested by removing its cover in order to access internal circuitry or by removing the battery from the battery compartment. Either way, the handset is tested by connecting a test fixture to the handset using an “internal” (i.e., not on the surface of the handset) connection. The handset may include an internal, dedicated connector called a Test Access Port (“TAP”). Once a connection has been established with a test fixture using a TAP or the like, the test fixture may send diagnostic message signals over the connection to internal processors or the like located inside the handset, e.g., digital signal processors, in order to conduct diagnostic tests. 
     Using internal TAPs to complete diagnostic tests is time-consuming because it requires that the handset (or base) be partially disassembled (i.e., to fix it) or partially assembled (i.e., when it is being made) to conduct the tests. Some cordless telephones have sought to solve this problem by placing the TAPs on the external surface of the handset (or base). While this may reduce the time it takes to complete the diagnostic tests, it has its drawbacks. First, placing TAPs on an external surface exposes them to a user. The risk is that the electrical contacts making up the TAPs could be damaged and rendered useless. Second, exposing TAPs results in a degradation in their conductivity over time. 
     Some have tried to use an RF link in order to carry out diagnostic tests. However, the production/manufacturing environment can be a harsh, frequency environment containing severe RF interference making the use of RF links impractical. 
     There is a need, therefore, for an improved means of completing diagnostic tests of a handset or base of a cordless telephone using a complementary test fixture/set-up. 
     Accordingly, it is an object of the present invention to provide for systems and methods for completing diagnostic tests of a handset or base of a rechargeable device without using internal TAPs. 
     Other objectives, features and advantages of the present invention will become apparent to those skilled in the art from the following description taken in conjunction with the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention there are provided systems and methods for completing diagnostic tests on rechargeable devices, such as a cordless telephone, using cradle contacts of a cordless handset or base. Using cradle contacts to complete diagnostic tests alleviates the problems associated with the cumbersome use of TAPS because the cradle contacts are located at or near the external surface of a cordless telephone handset or base. 
     An illustrative embodiment comprises a system which itself may comprise one or more devices such as a test fixture, cordless handset and/or cordless base. Each of these components in turn comprises cradle contacts for inputting and outputting diagnostic messages and a processor for controlling the generation, output and/or input of the diagnostic messages. The processor may comprise a digital signal processor, microprocessor or the like. 
     The cradle contacts of the test fixture, handset or base may alternatively comprise inductive cradle contacts while the diagnostic message signals may comprise signals not normally present during normal cradle charging, such as ASK message signals. These message signals have different frequencies than traditional charging signals. Embedded in the diagnostic message signals may be additional data which is used to insure the message signals are transmitted/received correctly, such as error checking and framing information. 
     In addition to cradle contacts and a processor, the test fixture, handset and/or base may also comprise a detector for separately detecting the diagnostic message signals from charging signals. This insures the two will not be confused by the processor. 
     In order to mark the beginning and end of a diagnostic test, the message signals may further comprise a first code or codes for indicating the beginning of a diagnostic test and/or a second code or codes for indicating the end of a diagnostic test. 
     The present invention and its advantages can be best understood with reference to the drawings, detailed description of the invention and claims that follow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 depicts a system comprising a handset of a cordless telephone linked to a test fixture via charging contacts, according to one embodiment of the present invention. 
     FIG. 2 depicts a system comprising a base of a cordless telephone linked to a test fixture via charging contacts according to another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, there is shown a block diagram of a system  18  which utilizes test fixture cradle contacts or means  4 , 6  and handset cradle contacts or means  3 , 5  to establish a link between a handset  1  and test fixture  2 . Though shown as being grouped in pairs, it should be understood that the cradle contacts are not so limited. The contacts  3 , 5  and  4 , 6  may be realized as multiple contacts, i.e., two or more contacts/contact pairs. In one embodiment of the invention, the cradle contacts  3 , 5  and  4 , 6  come into physical contact with one another in order to complete a physical, electrical connection between the handset  1  and test fixture  2 . In another embodiment of the invention, the cradle contacts  3 , 5  and  4 , 6  are not in physical contact with one another. Instead, the contacts establish an inductive connection or contact. In an illustrative embodiment of the invention the handset  1  comprises a cordless telephone handset though other rechargeable devices, such as a pager, etc. may be substituted. Though usually associated with a telephone, the word “handset” is not so limited. In the context of the present invention “handset” means a hand-held or mobile rechargeable, device. 
     It should be understood that the word “system” can be used to mean either the combination of the handset I and test fixture  2 , a combination which includes a base, or only one of these components. 
     Normally, once the cradle contacts  3 , 5  of the handset  1  have been placed into contact (either physical or inductive) with the contacts  4 , 6  of the test fixture  2  an electrical current is generated through the pairs of contacts  3 , 5  and  4 , 6 . This electrical current is referred to as a cradling signal. 
     This cradling signal is detected by the cradle contacts  3 , 5  and  4 , 6 , respectfully. The respective cradle contacts then inform processors or processing means  9 , 10  via internal buses  16 , 17  that the handset  1  has been cradled. After it is recognized that the handset  1  is cradled both the handset  1  and test fixture  2  begins to recharge the handset  1  using charging signals via the cradle contacts  3 , 5  and  4 , 6 . 
     This link can be used to conduct diagnostic tests. In one embodiment of the invention, the test fixture  2  transmits diagnostic message signals (“message signals”) to the handset  1  by controlling the frequency of the charging signals through cradle contacts  3 , 5  and  4 , 6 . As is known in the art, a message can be sent by turning a signal on or off. In one embodiment of the invention, the test fixture  2  sends messages to the handset  1  by turning the charging signal on and off at a high rate of speed. It should be understood that the diagnostic message signals must be different than normal charging or cradling signals or else the two signals may be confused. Varying the frequency of the diagnostic message signals is only one of many ways to distinguish these signals from charging or cradling signals. Other ways comprise placing a distinct message header at the beginning of each diagnostic message. Still other techniques are known in the art. 
     For example, the test fixture processor  10  is adapted to generate message signals and is further adapted to control the frequency of the message signals input by the cradle contacts  4 , 6  by controlling the signal applied to cradle contacts  4 , 6 . It may be said that the cradle contacts  4 , 6  are “toggled” to generate a series of on and off signals. In one embodiment of the invention, this series of on and off signals comprises amplitude shift keying (“ASK”) message signals. 
     The operation of the handset  1  according to one embodiment of the invention will now be described. The handset cradle contacts  3 , 5  receives the series of on and off message signals from the test fixture  2  via charging contacts  3 , 5 . These signals are then decoded using means known in the art. These decoded message signals are then used to initiate diagnostic tests between the test fixture  2  and handset  1 . It is now up to the handset  1  to generate message signals in response. 
     The handset processor  9  is similarly adapted to generate a separate set of message signals which are sent to handset cradle contacts  3 , 5 . The processor  9  is also adapted to control the output of the message signals by cradle contacts  3 , 5  by, more specifically, controlling the frequency of the charging signals. As before, the charging signals can be turned on and off by the handset  1  such that a series of on and off signals forms a responsive message which is then sent to the test fixture  2 . 
     Thus, the cradle contacts  3 , 5  and  4 , 6  serve multiple purposes; they are used to recharge the handset  1 , to detect a cradled state of the handset  1  and for sending diagnostic message signals. 
     In alternative embodiments of the invention, the test fixture  2  and/or handset  1  are further modified to send message signals. First, test fixture detector or means  12  and handset detector or means  11  may be used to detect each type of signal; the cradling signal used to detect whether the handset is in a cradled position, charging signals and the diagnostic message signals. In one embodiment of the invention the diagnostic message signals use different frequencies or symbol periods than the cradling or charging signals. As indicated before, these signals must be distinguished from one another in order to prevent either the handset  1  or test fixture  2  from erroneously confusing cradling/charging signals with a message signal. 
     It should be understood that the detectors  11 , 12  may further comprise a filter, filters or filter means adapted to detect only one of these signals at a time. Taken together each detector and cradle contact combination comprises an input/output unit (“I/O”)  7 ,  8 . 
     The diagnostic message signals input or output from either the handset  1  or test fixture  2  via the cradle contacts  3 , 5  and  4 , 6  may comprise additional formatting. In one embodiment of the invention, the message signals comprise error checking and framing information which are added by means known in the art prior to transmission by the handset/test fixture. Upon being received, a message signal is appropriately deframed and verified on both a word and message basis using means known in the art. The deframing and verification helps to rid the message signal of any spurious bounces and/or partial messages. 
     It should be understood that the cradle contacts  3 , 5  comprise TAPs for testing the handset  1 . During the manufacturing or servicing trouble shooting process, the handset  1  can be placed into the test fixture  2 . Once the test fixture  2  detects the presence of the handset  1 , by detecting a cradling signal, it sends diagnostic message signals to the handset  1  through cradle contacts  3 , 5  and  4 , 6 . Thereafter the diagnostic message signals are decoded using means known in the art and sent to processor  9 . Processor  9  is adapted to generate responsive message signals and controls the cradle contacts  3 , 5  so as to output the responsive message signals to the test fixture  2 . 
     In some cases the handset  1  will not immediately respond to the diagnostic message signals generated by the test fixture  2 . In another embodiment of the invention, the test fixture  2  waits a few seconds and then re-transmits diagnostic message signals over the charging contacts  3 , 5  and  4 , 6 . In still another embodiment of the invention, the diagnostic message signals initially sent by the test fixture  2  comprises a first code designed to initiate the start of a diagnostic test between the test fixture  2  and handset  1 . When the test fixture  2  has completed the transmission of diagnostic message signals, i.e. after the tests are completed, the test fixture  2  may alternatively transmit a diagnostic message signal which comprises a second code designed to inform the handset  1  that the testing process has been completed. It should be understood that the word “code” means both a single code or multiple codes. 
     The processors  9 , 10  may comprise digital signal processors, microprocessors, memory components or a combination of these devices. The functions carried out by the processors  9 , 10  may reside as instructions stored as program code in the processors  9 , 10  or in other devices known in the art. 
     FIG. 2 depicts another system  180  comprising a base  100  and test fixture  2 . The base may be troubleshooted or tested using diagnostic message signals transmitted over cradle contacts  103 , 105  and  104 , 106 . 
     Base processor  109 , base cradle contacts  103 , 105  and base detector  111  function in substantially the same fashion as their counterparts which comprise handset  1  described above. In an illustrative embodiment of the present invention the base  100  comprises a cordless telephone base, though in the context of the present invention “base” means a device which is used to cradle/hold and recharge a handset. 
     Though the above discussion focuses on systems and devices, it should be understood that the present invention also envisions methods for carrying out diagnostic tests between a test fixture and a device using cradle contacts. 
     It is to be understood that changes and variations may be made without departing from the spirit and scope of this invention as defined by the claims that follow.