Connection unit without equipment for a single module with modular design for mounting on a TH35 mounting rail in accordance with DIN EN 60715, the width of 1TE enables the installation of up to 12 REGs in standard electrical distribution boards, when installed as a device of protection class I, the potential equalization takes place via an integrated potential equalization spring directly via the mounting rail, which is to be connected to the building potential equalization via corresponding contact terminals, the module is protected from direct contact by a cover. When installed in protectively insulated distributors, protection class II is therefore maintained. The potential equalization spring must be removed for this., integrated dust protection flap (also available in color), the following modules can be installed: E-DAT module, E-DAT module coupling 180°, UAE module, OpDAT module LC-D and ST as well as coax modules, Attention: not suitable for C6, Amodul