SWITCHING DEVICE

PURPOSE:To constitute a system easily with extensivity from a minimum system to a large-scale system, by giving an extended interface and a simple controlling circuit to a switch of 1:2 which is the minimum unit constitution of a line switching mechanism. CONSTITUTION:A line switching mechanism 1 of 1:2 including a manual switch has a connection terminal 2 for a computer center current system of the interface, a connection terminal 3 for a computer center stand-by system, an MODEM connection terminal 4, and a connection terminal 5 for an extended system as a basic circuit and is provided with a switching control circuit 6. One of terminals 2 and 3 is switched and connected to the terminal 4 fundamentally. In this case, an optional number of switching devices are connected in parallel to change the switching of 1:2 to the switching of 2:3, 3:4, 4:5..., thereby extending the switching range.