Abstract: A device is disclosed in the field of user network access using xDSL processes. ADSL and VDSL processes have long been known. However, the object of the invention is to improve the known devices and processes, in particular the range of the subscriber line, the voltage supply and/or the migration capabilities of switching telephone networks and data transmission networks. This object is achieved by an intermediary unit having the following functionalities: termination of the PoADSL interface, i.e. termination of the ADSL connection (ADSL Interface User Side) at the CO (central office) end, power supply to the intermediary unit (30), provision of a user-oriented ADSL interface (ADSL Interface CO Side), provision of a user-oriented POTS interface (POTS Interface CO Side), an ADSL bridge function between the two ADSL interfaces, and a TDM/IP gateway function between the POTS and ADSL interfaces via the host controller; alternatively, a gateway function is also provided in an IP network.

Abstract: An ultrasonic transducer with a diaphragm and an embossed backplate is provided. Due to the embossing of the backplate, spacer disks are no longer necessary and the efficiency of the transducer is substantially increased.

Abstract: An electrodynamic acoustic transducer with a coil which projects into an air gap subject to an electromagnetic field, wherein an acoustic short circuit is prevented. The electrodynamic transducer has a membrane comprising two differently profiled portions, an acoustically effective central portion with a convexity in form of a spherical cap, and a ring-shaped bead which borders the central portion and serves to elastically support the membrane. The ring-shaped bead is arranged beneath the central portion and extends radially inwards starting from a coil seat of the coil. The air gap is sealed by means of a liquid or solid medium, such as ferrofluid, such that an acoustic short circuit between the front volume and the rear volume of the transducer is prevented.