A contactlessly or tactilely measuring measuring system having a multipurpose interface socket for accommodating and for connecting a contactlessly or tactilely measuring measuring device having a light transmitter and a light receiver, for determining the position of a tool or for determining the longest cutting edge of a rotating tool in a machine tool. The multipurpose interface socket has the following features: at least one mechanical stop, corresponding to a counterstop on the measuring device, for accommodating and repeatably placing the measuring device on the multipurpose interface socket; and at least one second fluid transfer point on the multipurpose interface socket, which corresponds to a first fluid transfer point on the measuring device.