System for accessing electrical circuits and relay switch thereof

A system for accessing a plurality of telephone wires which are two-wire, four-wire and six-wire circuits, including a common access test bus, a common control bus, a plurality of access shelves for connecting the circuits to the common access test bus, in which each access shelf is individually selectively controllable to connect the circuits to the common access test bus in response to control signals on the common control bus, and a test controller having a programmable data processor for selectively generating the control signals to individually control any one of the access shelves. A relay switch of the system for closing and splitting twelve wires includes a first relay having twelve contacts, corresponding to the twelve wires, respectively, for closing the twelve wires and for splitting the twelve wires into twenty-four wires, a second relay, having twelve contacts, for closing a first twelve of the twenty-four wires, each of two of these twelve contacts being on two of the first twelve wires, respectively, and a third relay, having twelve contacts, for closing a second twelve of the twenty-four wires, each of two of these twelve contacts being on two of the second twelve wires, respectively.