Abstract: A modular fiber-optic transceiver has an optoelectronic subassembly stack assembled in the beam direction and parallel to the plane of the mounting site. The subassembly is formed in various combinations of individually designed building modules for aligning, focusing, optoelectronic processing and eventual cooling. The subassembly is electrically conductive connected to a transceiver board and kept in perpendicular orientation to it by a snap fitting housing. The housing holds the cable plug of the fiber cable in position and transmits thereby the peripheral imposed mechanical load directly onto the mounting site. The modular building concept supports various techniques for fiber optic data transmission.