Abstract:
An apparatus and method are provided. The apparatus includes a display and a controller operatively coupled with the display. The controller is configured to determine whether the apparatus is coupled with an output device external to the apparatus, and to adjust a brightness of the display based at least in part on a determination that the apparatus is coupled with the output device.

Description:
PRIORITY 
     This is a continuation application of a U.S. patent application Ser. No. 13/091,486, filed Apr. 21, 2011; which claimed the benefit under 35 U.S.C. §119(a) of a Korean patent application filed on Apr. 30, 2010 in the Korean Intellectual Property Office and assigned Serial No. 10-2010-0041046, the entire disclosure of which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a mobile device having an ear jack interface. More particularly, the present invention relates to an earphone system and operation method thereof for identifying various input signals offered from an earphone connected to the ear jack interface and thereby for controlling a particular user-function in response to the identified signal. 
     2. Description of the Related Art 
     Normally, a mobile device denotes a type of electronic device that provides mobility and portability. With remarkable growth of related technologies, a great variety of mobile devices, such as a mobile communication device and a Personal Digital Assistant (PDA), are becoming increasingly popular these days. A typical mobile communication device has a module for supporting a mobile communication function and thereby allows voice and data communications with other mobile communication devices through a base station. A typical PDA has a Central Processing Unit (CPU), a memory unit, an Operating System (OS), and various programs and modules that operate based on the OS, and thereby allows various functions to collect, store, write and search information. 
     Some functions of the mobile device, e.g., a call function, an audio file play function, etc., inherently include a function to output audio signals through a speaker provided on the mobile device. Alternatively, a user of the mobile device may use an earphone to prevent sounds from being heard outside or to hear clearer sounds. 
     For a connection with an earphone, a conventional mobile device typically includes a 4-pole ear jack interface. However, this 4-pole ear jack interface only supports an audio signal output through right and left earphone speakers and an audio signal input through an earphone microphone. Additionally, the 4-pole ear jack interface merely recognizes the insertion of an earphone and then only performs audio input and output. Therefore, the utilization of such a conventional ear jack interface is limited. Even if any external device can be connected to the 4-pole ear jack interface, this may unfavorably cause great power consumption since a conventional mobile device should always monitor a connection of an external device by continuously detecting the value of an Analog Digital Converter (ADC) received through the ear jack interface. 
     SUMMARY OF THE INVENTION 
     Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. According, an aspect of the present invention is to provide an earphone system, a mobile device for supporting the earphone system, and an operation method for the earphone system, allowing various input elements to be connected to an ear jack interface of the mobile device with reduced power consumption. 
     According to an aspect of the present invention, an apparatus is provided. The apparatus includes a display and a controller operatively coupled with the display. The controller is configured to determine whether the apparatus is coupled with an output device external to the apparatus, and to adjust a brightness of the display based at least in part on a determination that the apparatus is coupled with the output device. 
     According to another aspect of the present invention, a method is provided. The method includes determining, at an electronic device including a display, whether the electronic device is coupled with an output device external to the electronic device, and adjusting a brightness of the display based at least in part on a determination that the electronic device is coupled with the output device. 
     According to still another aspect of the present invention, a non-transitory machine-readable storage device is provided. The storage device stores instructions that, when executed by one or more processors, cause the one or more processors to perform operations of determining, at an electronic device including a display, whether the electronic device is coupled with an output device external to the electronic device, and adjusting a brightness of the display based at least in part on a determination that the electronic device is coupled with the output device. 
     Other aspects, advantages and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating an earphone system in accordance with an exemplary embodiment of the present invention. 
         FIG. 2  is a block diagram illustrating a configuration of a mobile device in accordance with an exemplary embodiment of the present invention. 
         FIG. 3  is a schematic view illustrating an ear jack interface and an earphone in the earphone system in accordance with an exemplary embodiment of the present invention. 
         FIG. 4  is a schematic view illustrating signal identification in an ear jack interface in accordance with an exemplary embodiment of the present invention. 
         FIGS. 5 and 6  are flow diagrams illustrating a method for operating an ear phone system in accordance with an exemplary embodiment of the present invention. 
     
    
    
     Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. 
     The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
     It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
       FIG. 1  is a perspective view illustrating an earphone system in accordance with an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , the earphone system is composed of a mobile device  100  and an earphone  200 . Although the following disclosure is based on the earphone  200  connected to an ear jack interface of the mobile device  100 , this is exemplary only and not to be considered as a limitation of the present invention. Instead of the earphone  200 , any other equivalents, such as an external speaker, can be connected to the ear jack interface. 
     The mobile device  100  includes a display unit  140  and an ear jack interface  170  and may transmit or receive audio signals, generated during a content playback or a voice call, to or from the earphone  200  through the ear jack interface  170 . While connected to the earphone  200 , the mobile device  100  may identify signals created by and received from various input elements, such as volume up/down keys and call/stop keys, provided in the earphone  200 . Also, the mobile device  100  may control a particular user-function in response to the identified signal. The mobile device  100  may recognize the connection of the earphone  200  from an interrupt created when a header of the earphone  200  is inserted into the ear jack interface  170 , and may support particular functions related to the earphone  200 . Each individual element of the mobile device  100  will be described in more detail with reference to  FIG. 2  below. 
     The earphone  200  is a device that is connected to the ear jack interface  170  of the mobile device  100 . The earphone  200  receives audio signals from the mobile device  100  and converts the received audio signals into sounds. The earphone  200  of a 4-pole type may have an earphone header  210  that is inserted into the ear jack interface  170 , an earphone input unit  220  that has an earphone microphone (EAR-MIC), volume up/down keys  221 , call/stop keys  223 , and the like, and an earphone speaker  230  that may have left and right earphone speakers  231  and  233 . The earphone  200  acquires sounds and converts them into audio signals through the earphone microphone (EAR-MIC) and delivers the audio signals to the mobile device  100  through the earphone header  210 . In the earphone  200 , each element of the earphone input unit  220  may be activated and form a specific path according to a user&#39;s manipulation. Namely, each activated element of the earphone  200  may establish a path having a specific resistance value. Also, depending on a voltage value that is varied according to differences in resistance values in each path, the mobile device  100  may determine which element is activated in the earphone  200 . Related descriptions will be given later with reference to  FIG. 3 . 
     As discussed hereinbefore, the earphone system supports functions of the earphone  200  based on an interrupt created when the earphone  200  is connected to the ear jack interface  170 . Furthermore, the earphone system identifies various signals created by and received from various input elements, such as volume up/down keys and call/stop keys, provided in the earphone  200 , and controls a particular user-function in response to the identified signal. Therefore, a user can easily adjust an audio volume, make a call, stop a call, etc., by manipulating the 4-pole earphone  200  without directly handing the mobile device  100 . 
       FIG. 2  is a block diagram illustrating a configuration of a mobile device in accordance with an exemplary embodiment of the present invention. 
     Referring to  FIG. 2 , the mobile device  100  of this invention may include a Radio Frequency (RF) unit  110 , an input unit  120 , an audio processing unit  130 , a display unit  140 , a memory unit  150 , an ear jack interface  170 , and a control unit  160 . 
     The mobile device  100  having the above-specified elements is structured to create an interrupt when the earphone  200  is connected to the ear jack interface  170 . When such an interrupt occurs, the mobile device  100  can shift an audio path to the earphone  200 . Also, if any interrupt is caused by a voltage drop under a given value in the ear jack interface  170 , the mobile device  100  can detect the magnitude of a voltage drop and thereby identify the type of an input signal created by and received from the earphone  200 . The mobile device  100  can perform a particular user-function in response to the identified input signal of the earphone  200 . Each individual element of the mobile device  100  will be described below in more detail. 
     The RF unit  110  is a kind of communication module for supporting a mobile communication service of the mobile device  100 . The RF unit  110  may employ a Global System for Mobile communication (GSM) module, a Code Division Multiple Access (CDMA) module, or the like according to the type of mobile communication service and, based on such a module, establishes a communication channel with a mobile communication system. For this, the RF unit  110  may include an RF transmitter that up-converts the frequency of an outgoing signal and amplifies the signal, an RF receiver that amplifies with low-noise an incoming signal and down-converts the frequency of the signal, and the like. The RF unit  110  may be essential or not according to the type of mobile device  100 . Namely, if the mobile device  100  supports a mobile communication function based on a base station, the RF unit  110  is essential. However, in case of a monitor, a music player, etc. that requires no mobile communication function, the RF unit  110  may be omitted according to the designer&#39;s or manufacturer&#39;s intention. 
     More particularly, the RF unit  110  of this invention establishes a call channel with any other device in response to a user&#39;s manipulation and sends or receives audio signals to or from the other device. At this time, audio signals received by the RF unit  110  may be delivered to the earphone speaker  230  of the earphone  200  through the ear jack interface  170 . 
     The input unit  120  includes a plurality of input keys and function keys to receive a user&#39;s input action and to set various functions. The function keys may have navigation keys, side keys, shortcut keys, and any other special keys defined to perform particular functions. Additionally, the input unit  120  receives a user&#39;s key manipulation for controlling the mobile device  100 , creates a corresponding input signal, and delivers it to the control unit  160 . 
     More particularly, the input unit  120  may create various input signals for controlling user-functions of the mobile device  100  and send them to the control unit  160 . For instance, depending on a user&#39;s manipulation, the input unit  120  may create an input signal for entering or selecting a desired phone number, an input signal for trying to connect a call based on the desired phone number, an input signal for selecting and playing a desired file stored in the memory unit  150 , or the like, and deliver it to the control unit  160 . 
     The audio processing unit  130  may include a speaker (SPK) for outputting audio signals delivered from the control unit  160 , and a microphone (MIC) for collecting audio signals while a particular application is running. When the RF unit  110  is activated, the audio processing unit  130  may output audio signals received through the RF unit  110  or audio signals of selected content to the speaker (SPK). More particularly, before the earphone  200  is connected to the ear jack interface  170 , the audio processing unit  130  forms audio output and input paths based on the speaker (SPK) and the microphone (MIC). However, if the earphone  200  is connected to the ear jack interface  170 , the audio processing unit  130  removes the above paths based on the speaker (SPK) and the microphone (MIC) and forms new audio output and input paths based on the earphone-microphone (EAR-MIC) and the earphone speaker  230  in the earphone  200 . Therefore, audio signals of the mobile device  100  may be output through the ear jack interface  170  of the mobile device  100  and the earphone speaker  230  of the earphone  200 , and audio signals collected by the earphone microphone (EAR-MIC) may be input to the control unit  160  through the ear jack interface  170  and the audio processing unit  130 . 
     The display unit  140  represents information, including various menus of the mobile device  100 , input by a user or offered to a user. Namely, the display unit  140  may visually offer a variety of screen views in connection with the use of the mobile device  100 , such as an idle screen, a menu screen, a message writing screen, a call screen, and the like. 
     More particularly, the display unit  140  may enter into various states according to the connection of the ear jack interface  170 . That is, when the earphone  200  is connected to the ear jack interface  170  during a call, the display unit  140  may be automatically turned off to minimize power consumption. If any input signal for instructing a supply of power is input, the display unit  140  may be turned on to again display the screen that was displayed just before being turned off Additionally, when the earphone  200  is connected to the ear jack interface  170 , the display unit  140  may output a given message or any other equivalents to announce the connection to a user. This function may be disabled at a user&#39;s request. Furthermore, if any input signal is delivered from the earphone  200 , the display unit  140  may output a related screen. For instance, when receiving an input signal from the volume up/down keys or call/stop keys of the earphone  200 , the display unit  140  may display a given image related to a selected input key to offer a feedback to a user. This function may also be disabled at a user&#39;s request. 
     Meanwhile, the display unit  140  may be formed of a Liquid Crystal Display (LCD), Organic Light Emitting Diodes (OLEDs), or any other equivalent. In case of being fabricated in the form of a touch screen, the display unit  140  may act as an input unit as well. In this case, the touch screen may be composed of a display panel and touch sensors disposed thereon. Also, the mobile device  100  in this case may offer various menu screens available and suitable for the touch screen. 
     The memory unit  150  stores a variety of applications required for functions related to an exemplary embodiment of this invention or required for execution or playback of various types of files. If the mobile device  100  employs a touch screen, the memory unit  150  may store a key map, a menu map, etc. required for the operation of the touch screen. Here, the key map may have various well known types such as a keyboard map, a 3*4 key map, a QWERTY key map, or a special control key map suitable for the operation of a currently activated application. Also, the menu map may be a special menu map suitable for the operation of a currently activated application or a normal menu map having menu items offered by the mobile device. The memory unit  150  may consist of a program region and a data region. 
     The program region may store an Operating System (OS) for booting and operating the mobile device  100 , and applications required for performing various functions or required for executing or playing various files, such as a call application, a web browser for surfing on the Internet, a Moving Picture Experts Group (MPEG) MPEG-1 or MPEG-2 Audio Layer III (MP3) application for playing digital sounds, an image viewer application for showing image files, a video player application, and the like. More particularly, the program region may store an earphone support application for supporting the function of the earphone  200 . 
     The earphone support application is a specialized program that is activated when the earphone  200  is connected to the ear jack interface  170 , controls the shift of an audio path toward the earphone  200 , identifies an input signal received from the earphone  200 , and controls a particular user-function based on the identified input signal. For the above, the earphone support application may be loaded in the control unit  160  and may contain a routine for determining whether the earphone  200  is connected to the ear jack interface  170 , a routine for controlling the shift of audio output and input paths, a routine for identifying an input signal received from the earphone  200 , and a routine for controlling a particular user-function in response to the identified input signal. The user-function control routine may have a subroutine for controlling specific options of a currently activated user-function and a subroutine for activating a selected user-function or inactivating the activated user-function. 
     The data region stores data created or received while the mobile device  100  is used, and also may store various contents depending upon the type of the mobile device. In addition, if the display unit  140  is formed of a touch screen, the data region may store user&#39;s inputs received from the touch screen. More particularly, the data region may store an input signal table used for controlling user-functions based on the connection of the earphone  200 . The input signal table may define a mapping relation between types of input signals received from the earphone  200  and commands for executing user-functions. For instance, the input signal table may contain information about a command to increase a volume of a currently activated user-function in response to an input signal of the volume up key of the earphone  200 . Such an input signal substantially corresponds to a specific voltage value, so the input signal table may be used for the creation of commands according to various voltage values. 
     The ear jack interface  170  is provided on a side of the mobile device  100  in a form that allows the earphone header  210  to be inserted and then fixed. The ear jack interface  170  may have several pins such that various types of earphones can be used. A related description will be given later with reference to  FIG. 3 . 
     The control unit  160  controls a power supplying and initializing process for each element of the mobile device  100 . After initializing, the control unit  160  may perform a control for a particular user-function selected in response to the connection of the earphone  200 . More specifically, the control unit  160  may employ the above-discussed earphone support application and determine whether the earphone  200  is connected to the ear jack interface  170 . For this, the mobile device  100  may equip the ear jack interface  170  with terminals or electrode pins for keeping a reference voltage. The mobile device  100  may recognize the connection of the earphone  200  by detecting a drop of the reference voltage caused by the connection of the earphone  200 . Additionally, the control unit  160  may establish and control a signal path of the earphone  200  that is in contact with various electrode pins of the ear jack interface  170 . A related description will be given hereinafter with reference to  FIG. 3 . 
       FIG. 3  is a schematic view illustrating an ear jack interface and an earphone in an earphone system in accordance with an exemplary embodiment of the present invention. 
     Referring to  FIG. 3 , the ear jack interface  170  may have five electrode pins denoted respectively by reference numbers  1 ,  2 ,  3 ,  4  and  5 . Specifically, the first electrode pin  1  is a microphone electrode pin to be connected to an earphone microphone terminal M of the earphone header  210 . The second electrode pin  2  is a ground electrode pin to be connected to a ground terminal G of the earphone header  210 . The third electrode pin  3  is a right speaker electrode pin to be connected to a right earphone speaker terminal R of the earphone header  210 . The fourth electrode pin  4  is a left speaker electrode pin to be connected to a left earphone speaker terminal L of the earphone header  210 . The fifth electrode pin  5  is an optional electrode pin to be connected to the ground terminal G of the earphone header  210 . More particularly, the fifth electrode pin  5  may be used to generate an interrupt caused by the connection of the earphone  200 . Namely, when the fifth electrode pin  5  is grounded through the connection of the earphone  200  under conditions where a given reference voltage is applied to the fifth electrode pin  5 , the control unit  160  may determine that the earphone  200  is connected by recognizing a change of the reference voltage as an interrupt. 
     The third and fourth electrode pins  3  and  4  may be connected to the same terminal of the earphone header  210  in some types of earphones  200 . More specifically, if the earphone  200  is a stereo type, the third and fourth electrode pins  3  and  4  are connected respectively to the right and left earphone speaker terminals R and L which are separately formed. However, if the earphone  200  is a monaural type, the third and fourth electrode pins  3  and  4  may be connected to a single speaker terminal which is formed without distinguishing right and left speakers from each other. Nevertheless, since this invention is to identify input signals received through the earphone microphone terminal M, this invention may be applied to any type of earphone  200 , namely, regardless of mono or stereo. In this disclosure, a stereo type of earphone  200  is exemplarily used. 
     The earphone header  210  may have four terminals interconnected to the respective elements of the earphone  200 . Specifically, the earphone header  210  may have the earphone microphone terminal M, the ground terminal G, the right earphone speaker terminal R, and the left earphone speaker terminal L. The right earphone speaker terminal R is interconnected to the right earphone speaker  231 , and the left earphone speaker terminal L is interconnected to the left earphone speaker  233 . The earphone-microphone terminal M is interconnected to each of the earphone-microphone (EAR-MIC), the volume up/down keys  221 , and the call/stop keys  223  contained in the earphone input unit  220 . The volume up/down keys  221  include a volume up key and a volume down key, and the call/stop keys  223  include a call key and a call stop key. In  FIG. 3 , each key is represented to be a resistance. Namely, the first resistance R 1  indicates the volume up key, and the second resistance R 2  indicates the volume down key. Similarly, the third resistance R 3  indicates the call key, and the fourth resistance R 4  indicates the call stop key. More particularly, the resistance of each key may be different in value from the others. As discussed above, when the earphone header  210  is inserted into the ear jack interface  170 , it comes in contact with the respective electrode pins of the ear jack interface  170 . 
       FIG. 4  is a schematic view illustrating signal identification in an ear jack interface in accordance with an exemplary embodiment of the present invention. 
     Referring to  FIG. 4 , the ear jack interface  170  may have an Analog Digital Converter (ADC)  171  and a comparator  173 . The ADC  171  is connected between the first electrode pin  1  of the ear jack interface  170  and the comparator  173 . The comparator  173  compares a voltage delivered through the first electrode pin  1  with the reference voltage such that a selected user-function may be controlled according to comparison results. For instance, if only the earphone-microphone (EAR-MIC) is connected to the first electrode pin  1 , an input value of the comparator  173  becomes about 1.3V. In this case, an audio signal input through the earphone-microphone (EAR-MIC) may be offered to the control unit  160  along a signal path. 
     Meanwhile, when any selected key of the earphone input unit  220  is activated, a voltage applied to the first electrode pin  1  through the earphone-microphone terminal M may be dropped under 1.3V due to the resistance of the selected key. Here, the magnitude of a voltage drop may be adjusted through variations in resistance. Also, as discussed above, the respective keys of the earphone input unit  220  may have different resistance values. Such resistance values may be adjusted to cause a voltage drop under the reference voltage (e.g., 0.75V) of the comparator  173 . When any selected key is activated, a voltage drop occurs and the comparator  173  may offer comparison results depending on such a voltage drop to the control unit  160 . Therefore, even though the control unit  160  does not continuously monitor the comparator  173 , the control unit  160  can recognize a selected key by detecting the magnitude of a voltage drop output from the comparator  173 . The reference voltage of the comparator  173  may be varied according to a designer&#39;s intention. Also, the resistance values of the respective keys may be varied according to a designer&#39;s intention. 
     As discussed hereinbefore, the earphone system according to an exemplary embodiment of the present invention and the mobile device using the earphone system may identify various signals of the earphone input unit  220  in the earphone  200  when the 4-pole earphone  200  is connected, and may control a particular user-function in response to the identified signal. Although the earphone input unit  220  is described as having the volume up/down keys and the call/stop keys, this is exemplary only and not to be considered as a limitation of the present invention. Alternatively or additionally, the earphone input unit  220  may have any other various keys such as power turn-off key, a search key, etc. 
     Now, an exemplary method for operating an earphone system will be described in more detail with reference to  FIGS. 5 and 6 . 
       FIGS. 5 and 6  are flow diagrams illustrating a method for operating an ear phone system in accordance with an exemplary embodiment of the present invention. The following discussion will be focused on a process flow in the mobile device  100 . 
     Referring to  FIGS. 5 and 6 , when power is supplied to the mobile device  100 , the control unit  160  performs a booting process and initializes the respective elements of the mobile device  100 . Then, based on predefined schedule information, the control unit  160  outputs an idle screen on the display unit  140  in step  501 . If the schedule information contains instructions to activate a particular user-function, the control unit  160  may activate the user-function in this step according to the schedule information. 
     In step  503 , the control unit  160  may determine whether the earphone  200  is connected to the ear jack interface  170  of the mobile device  100 , namely whether the earphone header  210  is inserted into the ear jack interface  170 . If it is determined in step  503  that there is no connection of the earphone  200 , the control unit  160  may activate a selected user-function according to an input signal of the input unit  120  and then, based on the audio processing unit  130 , control a processing of audio signals in step  505 . 
     On the other hand, if it is determined in step  503  that the earphone  200  is connected to the ear jack interface  170 , the control unit  160  may shift current audio output and input paths to new paths based on the earphone  200  in step  507 . Thereafter, the control unit  160  may determine whether an input signal for making a call is received from the earphone  200  in step  509 . If so, the control unit  160  may try to make a call with the last phone number in a call history and also support a related user-function in step  511 . In step  512 , the control unit  160  may determine whether an input signal for stopping a call is received from the earphone  200 . If so, the control unit  160  may return to step  509 . 
     If it is determined in step  509  that there is no input signal for making a call, the control unit  160  may activate a selected user-function in response to any other input signal in step  513 . 
     In step  515 , the control unit  160  may determine whether an input signal corresponding to the volume up/down keys is received from the earphone  200 . If so, the control unit  160  may increase or decrease a sound volume of a currently activated user-function in step  517 . Then the control unit  160  may return to step  513 . 
     On the other hand, if it is determined that there is no input signal in step  515 , the control unit  160  may further determine whether the earphone  200  is disconnected from the ear jack interface  170 , namely whether the earphone header  210  is withdrawn from the ear jack interface  170  in step  519 . If it is determined in step  519  that there is no disconnection of the earphone  200 , the control unit  160  may return to step  513 . 
     If it is determined in step  519  that there is a disconnection of the earphone  200 , the control unit  160  may shift again the audio output and input paths based on the earphone  200  to the original paths based on the audio processing unit  130  while keeping a currently activated user-function in step  521 . In step  523 , the control unit  160  may determine whether an input signal for inactivating the current user-function is received. If it is determined in step  523  that there is no inactivating signal, the control unit  160  may return to step  521 . Alternatively, if it is determined in step  523  that there is an inactivating signal for the user-function, the control unit  160  may further determine whether an input signal for turning off the mobile device is received in step  525 . If there is no turn-off signal, the control unit  160  may return to the initial step  501 . 
     The control unit  160  may automatically lock the input unit  120  when the earphone  200  is connected. Additionally, when a call request signal is received from the external entity, the control unit  160  may deliver a related signal to the earphone  200 . Also, when a call acceptance signal is received from the earphone  200 , the control unit  160  may perform a function to make a call and then form audio paths based on the earphone  200 . 
     As discussed above, an interrupt occurs whenever the mobile device  100  receives any input signal from the earphone  200 . Since the control unit  160  can recognize the creation of a specific input signal from the occurrence of an interrupt, the mobile device  100  does not require a continuous monitoring for determining the creation of input signals by the earphone  200 . Therefore, unnecessary power consumption is reduced. 
     According to the above-discussed method for operating the earphone system, when the earphone  200  is connected to the ear jack interface  170 , the mobile device  100  can activate or inactivate a particular user-function or control options of the activated user-function in response to an input signal of the earphone  200 . 
     The above-discussed mobile device  100  may essentially or selectively include any other elements. For instance, the mobile device  100  may further include a short range communication module, a digital camera module, a wired or wireless data transmission interface, an Internet access module, a digital broadcast receiving module, and so forth. According to a digital convergence tendency, such elements may be varied, modified and improved in various ways, and any other elements equivalent to the above elements may be additionally or alternatively equipped in the mobile device  100 . Meanwhile, as will be understood by those skilled in the art, some of the above-mentioned elements in the mobile device  100  may be omitted or replaced with another. 
     Additionally, the mobile device  100  of this invention may include any type of electronic devices that has the ear jack interface  170 . For instance, the mobile device  100  may include communication devices, multimedia players and their application equipment, especially including many mobile communication terminals based on various communication protocols, a Portable Multimedia Player (PMP), a digital broadcasting player, a Personal Digital Assistant (PDA), a music player (e.g., an MP3 player), a portable game console, a smart phone, a notebook, a handheld personal computer, etc. 
     While this invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.