Abstract: A test system includes a test device configured to output a command address and a test dock for performing a test mode and to receive a comparison signal, and a memory device configured to enter the test mode, based on the command address, to set an initial value by the command address, to perform a calculation operation on the initial value according to a logic level combination of the command address to generate a row address and a command address during a pre-charge operation, and to compress and compare internal data output based on the row address and the column address to output the internal data as the comparison signal to the test device.

Abstract: An LED fixing device of a pixel module for a sign board is provided. The LED fixing device is installed on a front side of an LED panel of a road sign board, facilitates the downward flow of rainwater, and prevents the rainwater from being introduced into a pixel module. A method for manufacturing the LED fixing device is also provided. The method for manufacturing the LED fixing plate comprises the steps of extruding the fixing plate and the intercepting plate through a cavity of a mold integrally and continuously, cutting the integrally and continuously extruded fixing plate and intercepting plate at intervals of a predetermined distance, and punching the LED through-holes for fixing the LEDs in the fixing plate.