A method is disclosed for producing internal connections between two terminal equipments installed in a bus structure at one and the same subscriber of an integrated services digital network. Given the assumption of a base connection of the subscriber via a two-wire line having two base channels and one control channel, the transmitting and receiving directions are interchanged with respect to the base channel employed for the internal connection. This interchange occurs in the course of an existing connection to the exchange upon use of the control channel, and is interchanged at one of the pieces of terminal equipment which is participating in the internal connection. The method is useful in the environment of a boss/secretary arrangement.