Abstract: An image projection device includes: a panel unit configured to emit light rays; a projection optical system configured to receive the light rays emitted from the panel unit and to refract the light rays; a reflection unit having a reflection surface for receiving the light rays refracted by the projection optical system and reflecting the light rays; and a screen unit configured to display an image upon receiving the light rays reflected from the reflection surface. The panel unit, the projection optical system, the reflection unit, and the screen unit are arranged such that a distance of a shortest path among paths extending from the panel unit to the reflection unit through the projection optical system along a predetermined linear axis is longer than a distance of a longest path among paths extending from the reflection unit to the screen unit along the predetermined linear axis.

Abstract: An image projection device includes: a panel unit configured to emit light rays; a projection optical system configured to receive the light rays emitted from the panel unit and to refract the light rays; a reflection unit having a reflection surface for receiving the light rays refracted by the projection optical system and reflecting the light rays; and a screen unit configured to display an image upon receiving the light rays reflected from the reflection surface. The panel unit, the projection optical system, the reflection unit, and the screen unit are arranged such that a distance of a shortest path among paths extending from the panel unit to the reflection unit through the projection optical system along a predetermined linear axis is longer than a distance of a longest path among paths extending from the reflection unit to the screen unit along the predetermined linear axis.

Abstract: A method of controlling a mobile terminal, and which includes controlling, via a Windows processor, a plurality of peripheral devices of the mobile terminal; switching, via the Windows processor, the mobile terminal into a sleep state; granting, via an arbiter control processor, a control authority for controlling predetermined peripheral devices among the plurality of peripheral device to a 3G modem when the mobile terminal is switched into the sleep state; receiving, via a communication unit on the mobile terminal, an incoming call; and managing, via the 3G modem, circuit data and the predetermined peripheral devices for the incoming call.

Abstract: A method of controlling a mobile terminal, and which includes controlling, via a Windows processor, a plurality of peripheral devices of the mobile terminal; switching, via the Windows processor, the mobile terminal into a sleep state; granting, via an arbiter control processor, a control authority for controlling predetermined peripheral devices among the plurality of peripheral device to a 3G modem when the mobile terminal is switched into the sleep state; receiving, via a communication unit on the mobile terminal, an incoming call; and managing, via the 3G modem, circuit data and the predetermined peripheral devices for the incoming call.

Abstract: A method for managing a talk burst in a PTT service system comprises: allocating, by a PTT server, master authority to a particular PTT client; and controlling, by the PTT server, another PTT clients according to a talk burst management procedure selected by the PTT client having the master authority. The PTT server allocates the master authority to the PTT client initiating a session and the PTT client having the master authority freely controls the talk burst management procedure, so that session establishment can be smoothly controlled.

Abstract: A method for processing a talk burst of a PTT server when a PTT terminal requests permission to send a talk burst, but the talk burst has already been allocated to another PTT terminal. The PTT server sends to every PTT terminal having a session established therefor, a talk burst deny message including an ID of the PTT terminal having sent the talk burst request message. Then, each PTT terminal having received the talk burst deny message compares its own ID with the ID included in the talk burst deny message and outputs the comparison result, such that the request for permission to send the talk burst can be processed and every user can check the status information of all PTT terminals having a session established thereof.

Abstract: A server servicing a plurality of mobile communication systems for half-duplex communication is provided. The server comprises a transceiver to send and receive communication signals; a processor in operational relationship with the transceiver for processing executable code stored in a storage medium accessible by the processor, the executable code configured to cause the processor to detect a time duration in which a user continuously activates a half-duplex function.

Abstract: A mobile handset having a static preventing device comprises a handset body having components such as a PCB, a detachable battery, a locking member for securing the battery to or for releasing the battery from the handset body, a conductive contact plate located by the locking member, a ground provided at the battery for discharging static electricity, and a switching path from the conductive contact plate to the ground, wherein the switching path is operative when the battery is secured to or released from the handset body.

Abstract: An apparatus and method for controlling a speaker's volume of a push-to-talk (PTT) phone avoid an undesirably loud volume sound from the speaker that may be caused due to inadvertence of the user during a PTT call mode. While in a PTT call mode, physical contact between the user and a contact sensing unit, provided at a PTT button or at an earpiece, is sensed. The speaker volume is automatically adjusted according to how the user is holding the phone, as determined by the contact sensing unit. Thus, the emanation of undesirably loud sounds from a loud speaker of the phone (e.g. as occurs during a PTT session) can be prevented when it is determined that the user has the earpiece adjacent to their ear (e.g. as occurs during a normal mobile telephone conversation).

Abstract: A system and method for managing calls in a mobile communication system transmits information indicative of an operational state of a first mobile terminal to a second mobile terminal for display. The first terminal may be a called terminal and the second terminal a calling terminal. A user of the second terminal can therefore recognize a reason for a communication blockage if a call between the first and second terminals is lost.

Abstract: A method for managing talk burst authority of a mobile communication terminal for a PTT service comprises detecting a trigger signal generated from a voice activity detector in response to an audio input; activating a voice recognition processor to process the audio input; deactivating the corresponding voice recognition processor after a predetermined time has lapsed; transmitting a talk burst request message to the PTT server, when the audio input is for requesting permission to speak; transmitting the audio input to the PTT server; and storing the audio input in a buffer.

Abstract: An audio data retransmission method in a push to communicate (PTx) terminal for transmitting data by pressing a PTx key is provided. The method comprises transmitting data using a transmitting PTx terminal; storing the data in a buffer; and retransmitting the data when receiver requests retransmission due to a loss in communications.

Abstract: A call volume adjustment method and a mobile communication terminal using the same are disclosed. The method includes sensing if a pressure part of the mobile communication terminal is pressurized, determining the level of pressure applied to the pressure part upon sensing that the pressure part is pressurized, and adjusting the call volume of the mobile communication terminal according to the determined pressure level. Therefore, it is possible to adjust the call volume simply and conveniently without operating a specific key.

Abstract: An apparatus and method is provided for allowing an improved power key function of a mobile communication terminal that enhances user convenience by providing an independent backlight function for the power key when a mobile communication terminal is opened while in a power OFF state. By providing an independent backlight function for a power key of the mobile communication terminal, the present invention facilitates illuminating the power key when the mobile communication terminal is opened and in a power OFF state.

Abstract: An audio data retransmission method in a push to communicate (PTx) terminal for transmitting data by pressing a PTx key is provided. The method comprises transmitting data using a transmitting PTx terminal; storing the data in a buffer; and retransmitting the data when receiver requests retransmission due to a loss in communications.

Abstract: A menu display method for a mobile terminally, which includes logically operating a value of a first register indicating a current state of the mobile terminal and a value of a second register indicating a relevancy of a menu option available on the mobile terminal to the current state of the mobile terminal, and determining whether or not a selected menu is to be executed based on the logically operating step.

Abstract: A method for processing a talk burst of a PTT server when a PTT terminal requests permission to send a talk burst, but the talk burst has already been allocated to another PTT terminal. The PTT server sends to every PTT terminal having a session established therefor, a talk burst deny message including an ID of the PTT terminal having sent the talk burst request message. Then, each PTT terminal having received the talk burst deny message compares its own ID with the ID included in the talk burst deny message and outputs the comparison result, such that the request for permission to send the talk burst can be processed and every user can check the status information of all PTT terminals having a session established thereof.

Abstract: A mobile handset having a static preventing device comprises a handset body having components such as a PCB, a detachable battery, a locking member for securing the battery to or for releasing the battery from the handset body, a conductive contact plate located by the locking member, a ground provided at the battery for discharging static electricity, and a switching path from the conductive contact plate to the ground, wherein the switching path is operative when the battery is secured to or released from the handset body.

Abstract: A method for managing a talk burst in a PTT service system comprises: allocating, by a PTT server, master authority to a particular PTT client; and controlling, by the PTT server, another PTT clients according to a talk burst management procedure selected by the PTT client having the master authority. The PTT server allocates the master authority to the PTT client initiating a session and the PTT client having the master authority freely controls the talk burst management procedure, so that session establishment can be smoothly controlled.

Abstract: A server servicing a plurality of mobile communication systems for half-duplex communication is provided. The server comprises a transceiver to send and receive communication signals; a processor in operational relationship with the transceiver for processing executable code stored in a storage medium accessible by the processor, the executable code configured to cause the processor to detect a time duration in which a user continuously activates a half-duplex function.