PURPOSE: To facilitate a connection between the input/output terminal of a printed board and that of an external process, by using an adaptor substrate having a connector corresponding to an input/output connector of the printed board at an end part and an external process adaptor bonded at the other end part of the adaptor substrate, respectively.

CONSTITUTION: A pair of connectors 23a and 23b are attached to an end of a printed board PCB20 and an end of an adaptor substrate 22, respectively. In this case, the logical element of a process input/output device and the element of a signal converting circuit are packeged to the PCB20. At the same time, a terminal block 24 is attached to the other end of the substrate 22. The input/output terminal of an external process 21 is connected to the block 24 of the substrate 22 via an input/output cable 25. The PCB20 is connected to the substrate 22 with joint of connectors 23a and 23b. Thus the connection is possible between the PCB20 and the process 21. If a connector is used in place of the block 24, it is convenient to connect a connector to the tip of the cable 25 of the process 21.