Abstract: A test mode circuit for use in a data system includes a test mode code latch for receiving a test mode code. A switch, which when turned on, couples the test mode code latch to the input so that the test mode code can be transferred from the input to the test mode code latch. A test mode command decoder is coupled to the test mode code latch for decoding the test mode code to initiate a test mode of operation in the data system. A data storage unit is coupled to the test mode command decoder for storing a data bit which corresponds to a low voltage test mode enable signal. The data bit may be modified during the test mode of operation. A low voltage test mode circuit is coupled to the data storage unit which, after first being enabled by the low voltage test mode enable signal, can be controlled to turn the switch on and off. An enable signal generation circuit couples the low voltage test mode circuit to the switch for turning the switch on and off.

Abstract: A calibrate and run bias voltage control method for an optical delay system utilizing a plurality of voltage controlled switches which may experience bias drift wherein during calibration an output optical power error signal of the system is monitored while rapidly changing the bias voltages to the switches according to a desired algorithm and setting the bias voltages at a the level achieved when the output error signal falls below a predetermined tolerance level.

Abstract: A method efficiently manages equipment and personnel within a closed passage such as a tunnel and the like. At a first step, sensing values measured by sensors through a corresponding AUX device in each set are monitored to generate a set of monitored sensing values. At a next step, each monitored sensing value in the set is compared with a corresponding predetermined threshold value to provide information corresponding to the comparison result. At a final step, it is decided whether or not a trouble is detected within the passage based on the comparison result information to produce information representing the decision result and, in response to the decision result information, automatically sending predetermined emergency guide information to each of predetermined agencies and controlling the operation of each of components within the passage.