Abstract: A dual mode user terminal for a calling party can make calls over both a conventional cellular network and a packet data network using VoIP protocols. If the called party is not available to receive a VoIP call over the packet data network, the user terminal for the calling party can request a third party user terminal available on the packet data network to relay the call between the calling party and the called party.

Abstract: A digging system includes a machine having a machine frame, and an implement assembly mounted to the machine frame. The implement assembly includes an elongate boom and a trenching mechanism having a plurality of drawing cutters coupled with an endless drive chain movable about a drive system mounted to an elongate boom. The implement assembly further includes an undercutting mechanism having first and second rotating cutters projecting in opposite axial directions from the distal boom end. The implement assembly defines a compound projection profile in a plane which includes first and second axes of rotation of a drive wheel and guide wheel of the drive system. The compound projection profile includes a relatively narrow proximal stem segment corresponding to the trenching mechanism and a relatively broad distal footing segment corresponding to the undercutting mechanism.

Abstract: Methods and apparatuses are provided for constructing an underground wall in a trench, include using multiple chains on an endless chain cutter and individually controlling the speed and/or direction of the chains, various configurations of cutter bits and agitator bars on the chains, a technique for assembling the endless chain cutter in a horizontal position outside of a starter trench, then erecting the endless chain cutter to a vertical position in the starter trench. A guide frame straddles the starter trench. The endless chain cutter is repeatedly moved within the guide frame, then the guide frame is re-positioned until the entire length of the trench has been excavated. A central portion of the trench may be cut deeper than outer portions to create interlocking joints between adjacent wall sections and added stability for the resulting wall. Side gap barriers seal gaps between the sides of the endless chain cutter and side walls of the trench.

Abstract: A method of operation to effectively excavate an underdrain in the field ground having a long service life and ensuring that the underdrain will not be closed after a long period of time and a device for such operation. The method includes attaching a plurality of buckets to an endless chain, driving the endless chain to excavate a slit in the field ground, reforming inner side walls of the slit by a reformer, pressing soil from both sides of the slit later ally inwardly by a pressing member attached to the reformer to form a block to separate the slit into an upper space and a Iover space, and charging the upper space with discarded dirt.

Abstract: An excavator for constructing an underground continuous wall includes an extensible guide post, an endless chain extending around a chain driving wheel provided at the upper portion of the guide post and a chain sprocket at the lower portion of the guide post, and a number of cutter bits and a number of agitator bars alternately arranged on the chain to form an endless chain cutter and a jet pipe provided in the guide post to be connectable to a fluid supply source and having a number of nozzles branched from the jet pipe. The endless chain cutter is detachably fixed to the end of the boom extending from a vehicle traveling on the ground. The endless chain cutter may be vertically movably mounted on the boom so as to be vertically driven by a driving device. The cutter bits are changeable with harder cutter bits according to obstacles in the ground.