Abstract: In a multiplex and transmission system, multiplex equipment in one station having a plurality of low speed units and a high speed unit, is connected through two transmission lines to other multiplex equipment in another station having a plurality of low speed units and a high speed unit. The system further includes a test circuit of multiplex equipment comprising a switch group for connecting the low speed units in tandem, on an input line and an output line of the low speed unit in each channel in the one station. When a test is carried out, the low speed output of each low speed unit is connected to the low speed input of the next low speed unit. A low speed signal loop back is executed in the low speed units in the other station. A pulse pattern generator is connected to the low speed input of the low speed unit in the first channel in the one station and a certain pulse pattern is supplied to the low speed input.

Abstract: A method of switching from one synchronizing signal source to another in a synchronous data communication network in which a plurality of stations are connected to each other via lines and A plurality of synchronizing signal sources are provided inside or outside the stations; the when a failure occurs a synchronizing signal source is replaced by another synchronizing signal source in correspondence to the failure so that the data communication may be continued. Specifically, flag bit data, indicating whether or not the synchronizing signal transmitted via the line is available, are set in the signal including the synchronizing signal and transmitted via the line. When a failure occurs in any of the plurality of synchronizing signal sources, a table provided in each station and specifying the order of priority for selection of a synchronizing signal source is referred to, and a synchronizing signal source is selected for each station in accordance with said flag bit data.

Abstract: In a first apparatus, transmission signals are inverted in a sending side and are restored in a receiving side in one direction of two-way communication, and transmission signals are not inverted in another direction, to thereby distinguish a signal reflected at a fault point of an optical fiber from normal receiving signals from the station of the other party. In a loopback test, an inverter provided in the receiving side of the former direction is bypassed and an inverter is inserted in the receiving side of the latter direction. In a second apparatus, overhead information for identifying stations is added in a sending side. In a receiving side, the overhead is extracted. The extracted overhead is compared with an identifier of the station of the other party in a normal operation and is compared with an identifier of the station itself in a loopback test.

Abstract: The present invention is concerned with a working machine in the form of a construction machine including booms 2 and a bucket 4 such as a wheel loader, a shovel loader or the like. When a scooping operation is performed by alternately repeating a tilting operation with the use of only a bucket operation lever 16 while a boom operation lever 15 is held at a boom kick-out position, a lifting operation for the booms 2 and a tilting operation for the bucket 4 while the boom operation lever 15 is shifted to a neutral position, a lift speed of the booms 2 is variably controlled to a speed corresponding to a tile speed of the bucket or an angle of the booms whereby the tilt speed is harmonized with the boom speed.