Telecom 605 Plug

This is the standard Telecom / PMG plug on Australian Phones from the 1960s to the 1990s. They are still common today. The 605 plug fitted into the 610 socket

Standard three pin six conductor. The non-conducting spigot of the original 605 plug was provided with a hole for a countersunk screw, allowing the plug to be fixed in a wall-mounted socket. Removal then required first removing the socket cover, to allow this retaining screw to be removed. In this way a semi-permanent connection, requiring tools for disconnection, could be achieved. Most phone installations were only one phone in one location.