Abstract: A method for controlling a service device through a smart terminal based on near field communication (NFC) includes the steps of: activating NFC between the smart terminal and the service device; handing over the communication between the smart terminal and the service device to a secondary network through the NFC; executing, by the start terminal, a web contents execution program; providing, by the service device, control codes to the smart terminal; preparing, by the smart terminal, to utilize the control codes; displaying, by the smart terminal, a control/service screen of the service device on the web contents execution program by utilizing the control codes; detecting, by the web contents execution program, a user manipulation on the control/service screen; and transmitting, by the web contents execution program, a request defined in the control codes to the service device in response to the user manipulation.

Abstract: A method for controlling a service device through a smart terminal based on near field communication (NFC) includes the steps of: activating NFC between the smart terminal and the service device; handing over the communication between the smart terminal and the service device to a secondary network through the NFC; executing, by the start terminal, a web contents execution program; providing, by the service device, control codes to the smart terminal; preparing, by the smart terminal, to utilize the control codes; displaying, by the smart terminal, a control/service screen of the service device on the web contents execution program by utilizing the control codes; detecting, by the web contents execution program, a user manipulation on the control/service screen; and transmitting, by the web contents execution program, a request defined in the control codes to the service device in response to the user manipulation.

Abstract: A power failure shunting office line restoring circuit includes: a first relay having an office line tip port connected to a common port for connecting the tip port of the office line to a separate emergency telephone or a key telephone office line accommodating circuit in accordance with a first relay control signal; a second relay having an office line ring port connected to a common port for connecting the ring port of the office line to the emergency telephone or the key telephone office line accommodating circuit in accordance with a second relay control signal; a controller for generating the first and second relay control signals according to a power supply state or emergency telephone use state detection signal; first and second relay drivers for driving the first and second relays in accordance with the first and second relay control signals generated by the controller, and a detector connected to the first relay for detecting the use of the emergency telephone and for outputting the use state detect

Abstract: A balanced network in a keyphone system has a filtering unit which is composed of: first and second filtering circuits, formed on the transmission path and having an inverted-phase feature, for adjusting the level of the transmission signal and for removing spurious waves thereof; an inverted-phase signal branch point disposed between the first and second filtering circuits, for branching out an inverted-phase transmission signal; an operational amplifier disposed on the reception path, for adjusting a level of the reception signal; a signal superimposing node disposed ahead of an input of the operational amplifier; and a feedback signal level adjusting circuit disposed between the inverted-phase signal branch point and the signal superimposing node, for adjusting the level of the inverted-phase transmission signal which has been branched out from the inverted-phase signal branch point so as to reduce a feedback signal, transmitted from the transmission path to the reception path through the common node, to a