The invention is directed to a method for recognizing, in a system having a first terminal device and a second terminal device connected to a two-wire subscriber line, an off-hook condition of the second terminal device (2; 3) at the two-wire subscriber line (4) in a switching center (5) or the like, in which the off-hook condition of a first terminal device (3; 2) working in a different frequency band than the second terminal device at the same two-wire subscriber line is recognized by acquiring a loop d.c. (i) and comparing it to a threshold. For reducing the consumable power to be made available in the switching center (5), the invention provides that the loop d.c. (i) is compared to a second threshold that is higher than the first threshold by the minimally required current level in the operation of the first terminal device (3; 2). All off-hook conditions can thus be dependably recognized in the fundamentally same way without providing additional devices and therefore having to make additional consumable power available.