Abstract: A universal remotely controlled test interface test unit is adapted to be connected through plug connections to an on-site computing system having one or more central processing units and associated peripheral equipment. The test interface unit is provided with a limited function keyboard control for initiating tests and a transceiver for communicating with a data processing unit at a remote location which supplies format and control signals for use by the test interface unit and data signals to be communicated to the on-site computing system. The data signals received by the test interface unit are first entered into a buffer register to provide parallel outputs. The format control signals activate logic gating signals to cause the data signals in the buffer register to be arranged in a control register in a format which is compatible with the equipment to be tested.