Abstract:
A method of providing data communication services between an external electronic device such as a personal computer which is connected to a communication device such as a mobile phone, comprising the steps of: periodically checking a connection state to generate connection state data, storing said connection state data in a memory, and determining whether to provide said data communication services according to said stored connection state data. A device for performing the method is also disclosed.

Description:
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application entitled METHOD OF PROVIDING A DIGITAL MOBILE PHONE WITH DATA COMMUNICATION SERVICES earlier filed in the Korean Industrial Property Office on Sep. 7, 1998, and there duly assigned Ser. No. 36798/1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method of providing a mobile phone with data communication services, and more particularly a method of providing data communication services for a mobile phone connected to external electronic equipment, such as a personal computer (PC) or fax machine, via a data cable. 
     2. Description of the Related Art 
     Generally, a mobile phone may be used to provide data communication services for equipment connected to the mobile phone, such as a personal computer (PC) or fax machine connected to the mobile phone, by exchanging data files with the computer or fax machine through a radio channel allotted for voice communication. The connection between the external equipment is typically through the provision of a data cable. However, conventional mobile phones have no means of detecting the status of the connection between the data cable attached to the PC and the mobile phone. Consequently, if the data cable between the mobile phone and the PC is inadvertently disconnected during data communication, the mobile phone continues the radio channel communication as if it were still connected to the computer or fax machine, without detecting the disconnection. This may lead to a mobile phone service provider billing a user for time during which the user did not receive data communication services due to the undetected disconnection of the data cable. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a mobile phone with a method of terminating a data communication connection when a data cable between a mobile phone and a personal computer (PC) is inadvertently disconnected during data communication, thereby not exposing a user to billing for time during which he was not receiving data communication services. 
     The present invention, a method of providing data communication services for a PC connected by a data cable to a mobile phone, comprises the steps of periodically checking a connection state of the data cable to generate connection state data, storing the connection state data in a memory, periodically updating the connection state data, and determining whether to provide data communication services based on the connection state data. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described more specifically with reference to the attached drawings. 
     FIG. 1 is a block diagram illustrating a digital mobile phone and its connection through a data cable to an external PC in accordance with the present invention; 
     FIG. 2 is a flow chart illustrating a process for checking the connection state of the data cable connected between the mobile phone and the PC in accordance with the present invention; and 
     FIG. 3 is a flow chart illustrating a process for providing data communication services in the mobile phone according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, in which like reference numerals represent similar or identical elements, in particular with respect to FIG. 1, data communication between a mobile phone and a personal computer (PC)  100 , is controlled by a central processing unit (CPU)  211  which controlls the functions of the mobile phone. Programs for controlling the functions of the mobile phone are stored in a program memory  212 , which may be a flash memory. Data temporarily generated from the operation of the mobile phone is stored in a data memory  213 , which may be a random access memory (RAM). A nonvolatile memory  214 , which is provided to store phone numbers for shortcut dialing, and may include system parameters, may be an electrically erasable programmable read-only memory (EEPROM). A key pad  215  generates key signals representing commands and data for input to CPU  211 . State information during operation of the mobile phone is displayed on a display  216  under control of CPU  211 , where the display  216  may be a liquid crystal display (LCD). The communications part of the mobile phone comprises an RF (radio frequency interface) part  217 , frequency conversion part  218 , modem  219 , and signal processing part  220 , all of which are controlled by CPU  211 . The signal processing part  220  comprises the following (not shown): an encoder (interleaver &amp; encoder), decoder (deinterleaver &amp; decoder), vocoder, and PCM codec (coder/decoder). For simplicity, the transmitting and receiving parts are not separately shown in the drawing. Also omitted in the drawing are lines representing the control of CPU  211 , a sound signal processing circuit, and other components which are not required for an understanding of the present invention. 
     In transmission mode, data is encoded by the signal processing part  220 , modulated by the modem  219 , subjected to frequency-up-conversion by the frequency conversion part  218 , band-pass filtered and amplified by the RF part  217 , and finally aired through the antenna ANT. In receiving mode, a weak radio frequency signal coming through the antenna ANT is low-noise amplified and filtered into the base band by RF part  217 , subjected to frequency-down-conversion by the frequency conversion part  218 , demodulated by the modem  219 , and decoded by the signal processing part  220 . 
     CPU  211  performs data communication with PC  100  through a UART (Universal Asynchronous Receiver Transmitter)  150  in asynchronous transfer mode (ATM). UART  150  is a serial/parallel conversion ATM transceiver that enables data communication between the mobile phone and PC  100 , through the provision of data cable  110 , which supports serial communication used for exchanging data between the mobile phone and PC  100 . While the preferred embodiment of the present invention provides for connection between the PC  100  and the mobile phone by means of data cable  110 , it is also contemplated that other connection means may be provided, such as a wireless link or remote connection. 
     FIG. 2 describes the detection of the connection state of the data cable  110  with respect to the external equipment (i.e. PC  100 ) and the mobile phone. In step  311 , CPU  211  repeatedly counts a predetermined time for periodically checking the state of the serial port of UART  150 . When the given time has elapsed in step  313 , CPU  211  checks the serial port of UART  150  in step  315  to determine whether the connection between UART  150  and PC  100  by the data cable  110  is intact. When the connection of the data cable  110  is found to be intact in step  317 , CPU  211  sets a data cable flag stored in a given region of the data memory  213  as “1” in step  319 . However, if the connection of the data cable is found to be disconnected in step  317 , CPU  211  sets the data cable flag as “0” in step  318 . The data cable flag may alternatively be defined in a given region of the nonvolatile memory  214  instead of the data memory  213 . Subsequent to step  318  or  319 , the process returns to step  311  and is repeated. 
     Referring now to FIG. 3, when the mobile phone is in standby mode in step  411 , CPU  211  checks in step  413  for call data received by the mobile phone via communications part  217 - 220  as shown in FIG.  1 . If call data has not been received in step  413 , other functions are performed at step  428 , such as editing phone numbers, entering key inputs, etc. However, if call data has been received in step  413 , it is analyzed in step  415  to determine in steps  417 A and  417 B whether it represents voice communication services or data communication services. If in step  417 A the call data represents voice communication services, then voice communication services are initiated at step  430 ; otherwise, the process goes to step  417 B. If the call data represents data communication services in step  417 B, the process goes to step  419  to retrieve the periodically revised data cable flag from the data memory  213  (or non-volatile memory  284 ), and then the process goes to step  421 ; otherwise, the process goes to a data service cancelling routine at step  427 . In step  421 , the connection state of the data cable is determined according to the value of the data cable flag. If the flag is detected as “1”, the data cable is normally connected with UART  150  so as to properly provide data communication services and enters the data communication service mode in step  423 . At this point, the data communication services routine is called at step  425 . If the data cable flag is not detected as “1” in step  421 , the connection of the data cable is abnormal, or disconnected, and data communication services are not initiated and data service is cancelled at step  427 . Furthermore, the processes of FIGS. 2 and 3 are repeatedly performed to continuously check the connection state of the data cable during an ongoing call, and to cancel data communication services if the data cable flag is not detected as “1”. 
     Thus, the invention provides a means for continuously checking the status of the connection between a mobile phone and the PC  100 , typically through the provision of data cable  110 , so that the user may avoid unjustified billing fees during inadvertent disconnection of the data cable  110 . 
     While the present invention has been described with specific embodiments accompanied by the attached drawings, it will be appreciated by those skilled in the art that various changes and modifications may be made thereto without departing from the gist of the present invention. For example, the invention is applicable to various communications devices, such as a microwave relay or a communications satellite, and is not restricted to a mobile telephone. As a further example, the invention is applicable to various communications links between the mobile phone and the connected PC, such as a wireless communications link, and is not restricted to a data cable link.