A communications system contains a base station (8) with a transmitter/receiver unit (10) for communication signals and a transmitter unit (14) for location interrogation signals; a response transmitter (20) with a transmitter/receiver unit (22) for the communication signals, and a receiver unit (26) for location interrogation signals. An interior space (2) which is located within the operating range of the communications system has walls (4) which are impermeable to one frequency range. The communication signals are transmitted and received in a frequency range to which the walls 4 are permeable. The location interrogation signals are transmitted in the frequency range to which the walls are impermeable.