Abstract: An etchant composition includes: an inorganic acid compound at 9.0 wt % to 9.9 wt %; an inorganic salt compound at 5.0 wt % to 10.0 wt %; an organic acid compound at 35 wt % to 45 wt %; a lactate-based compound at 10 wt % to 20 wt %; a nitrogen cyclic compound containing oxygen at 0.1 wt % to 1.0 wt %; and a remaining amount of water such that a total weight of the etchant composition is 100 wt %, wherein the inorganic acid compound is an etchant composition having an acid dissociation constant (pKa) value of ?1.0 to ?3.0.

Abstract: An etchant composition includes: an inorganic acid compound at 9.0 wt % to 9.9 wt %; an inorganic salt compound at 5.0 wt % to 10.0 wt %; an organic acid compound at 35 wt % to 45 wt %; a lactate-based compound at 10 wt % to 20 wt %; a nitrogen cyclic compound containing oxygen at 0.1 wt % to 1.0 wt %; and a remaining amount of water such that a total weight of the etchant composition is 100 wt %, wherein the inorganic acid compound is an etchant composition having an acid dissociation constant (pKa) value of ?1.0 to ?3.0.

Abstract: The present invention discloses a protection-switching apparatus and method in an asynchronous transfer mode (ATM) system with ring topology. In the invention, the ONU detects a trouble, or abnormal states, of an optical path connected with the ONU itself; the ONU performs the protection-switching function by receiving an ATM cell from the opposite direction of the optical path having the trouble; the software unit of the ONU inserts a node identification data (NID) of the ONU to the APS register of the optical path of normal states; and the hardware unit of the ONU generates the APS cell by performing mirroring of the APS register to the VCI area of the APS cell, and transmits the APS cell in the same direction as the direction of the optical path of abnormal states. Therefore, the protection-switching apparatus and method in an ATM system with ring topology of the present invention have the advantage of reducing switching delay time and switching load.

Abstract: A multi digital subscriber line access multiplexor M-DSLAM system, connecting with an asynchronous transfer mode ATM network, linking with multiple data transmission service networks, and multiple subscriber receiving/transmitting units to perform subscriber line collection function and enable a wideband high-speed data receiving/transmitting operation among the numerous subscribers, The M-DSLAM system incorporates multiple ATM cell buses, an NIU, multiple xDSL service unit, a shelf interface unit SIU, and a main control unit MCU. Therefore, the M-DSLAM system can provide a wideband high-speed data service system, that supports high capacity processing ability and various services including a dialogue service with motion picture, such as a videoconference, a video medical service, VoD, and a voice service based on voIP. This M-DSLAM system advantageously enables on a substantial increase in the number of subscribers while significantly reducing the area occupied by the M-DSLAM system.

Abstract: A host digital terminal HDT performs backbone functions to a subscriber access network, while the network side of the HDT is connected to many data transfer networks and the other side of the HDT is connected to many optical network units ONUs. The HDT performs mutual interactions to many units by the ATM cell switching or by the STM cross connections, while the units perform predetermined functions, such as ANIU, HNIU, HIU, and HTIU. Therefore, the HDT overcomes capacity limits according to mutual interactions among the units through the conventional common bus.

Abstract: The present invention includes an optical network unit ONU, connected to a backbone network including a host digital terminal HDT and a digital subscriber line access multiplexor DSLAM of a high-speed data service system, and connected to multiple subscribers, for performing subscriber concentration functions, while the ONU includes a common unit board CUB, interfaced with the backbone network, for extracting an ATM cell, performing a full-duplex ATM cell processing function, performing a transmission test for the ATM cell and associated data, and controlling mutual operations among each of the unit boards and data flows; multiple xDSL service unit boards for performing a subscriber interface after converting the ATM cell from the CUB to an analog signal and thereof, for dividing the ATM cell into a high frequency component for data area and a low frequency component for a voice area, and for transmitting the ATM cell to the subscribers, or vice versa; and a shelf including multiple slots for plugging-in mult

Abstract: The present invention includes an optical network unit ONU, connected to a backbone network including a host digital terminal HDT and a digital subscriber line access multiplexor DSLAM of a high-speed data service system, and connected to multiple subscribers, for performing subscriber concentration functions, while the ONU includes a common unit board CUB, interfaced with the backbone network, for extracting an ATM cell, performing a full-duplex ATM cell processing function, performing a transmission test for the ATM cell and associated data, and controlling mutual operations among each of the unit boards and data flows; multiple xDSL service unit boards for performing a subscriber interface after converting the ATM cell from the CUB to an analog signal and thereof, for dividing the ATM cell into a high frequency component for data area and a low frequency component for a voice area, and for transmitting the ATM cell to the subscribers, or vice versa; and a shelf including multiple slots for plugging-in mult

Abstract: The present invention discloses a protection-switching method in an asynchronous transfer mode ATM system with ring topology, with the protection-switching method of an ONU including the ONU detecting a trouble, or abnormal states, of an optical path connected with the ONU itself, the ONU performing the protection-switching function receiving an ATM cell from the opposite direction of the optical path having the trouble, the software unit of the ONU inserting a node identification data NID of the ONU to the APS register of the optical path of normal states, and the hardware unit of the ONU generating the APS cell by performing mirroring of the APS register to the VCI area of the APS cell, and transmitting the APS cell to the same direction with the direction of the optical path of an abnormal states. Therefore, a protection-switching method in an ATM system with ring topology of the present invention has an advantage of reducing a switching delay time and a switching load.

Abstract: A host digital terminal HDT is for performing backbone functions to a subscriber access network, while the network side of the HDT is connected to many data transfer networks and the other side of the HDT is connected to many optical network units ONUs.

Abstract: A multi digital subscriber line access multiplexor M-DSLAM system, connecting with an asynchronous transfer mode ATM network, l inking with multiple data transmission service networks, and multiple subscriber receiving/transmitting units to perform subscriber line collection function and enable a wideband high-speed data receiving/transmitting operation among the numerous subscribers, The M-DSLAM system incorporates multiple ATM cell buses, an NIU, multiple xDSL service unit, a shelf interface unit SIU, and a main control unit MCU. Therefore, the M-DSLAM system can provide a wideband high-speed data service system, that supports high capacity processing ability and various services including a dialogue service with motion picture, such as a videoconference, a video medical service, VoD, and a voice service based on voIP. This M-DSLAM system advantageously enables on a substantial increase in the number of subscribers while significantly reducing the area occupied by the M-DSLAM system.

Abstract: The present invention discloses a remote control and management system comprising a remote management unit for registering remote sites, connection setting and system setting and managing by being interacting with a local terminal which is connected with a plurality of monitoring devices for monitorng the remote site, a remote monitoring unit for outputting audio/video data input from the monitoring devices, and event detecting unit for analyzing the monitored data transmitted from the monitoring devices, generating an event and reporting event occurrenct to the remote management unit and the remote monitoring unit, and a remote retrieving unit for retrieving and outputting the audio/video data corresponding to the event.

Abstract: A digital processing phase lock loop for use in a synchronous micro-wave transmitter includes: a reference clock receiving unit for receiving an electric signal or an optical signal of 8 KHz as an reference clock from an external signal input unit or a switching unit; a phase comparator for comparing the reference clock output from the reference clock receiving unit with a self-clock feedback depending on a counter clock of 19.