IEC 62149-2:2014 covers the performance specification for 850-nm discrete vertical cavity surface emitting laser (VCSEL) devices of transverse multimode types used for fibre optic telecommunication and optical data transmission applications. The performance standard contains a definition of the product performance requirements together with a series of sets of tests and measurements with clearly defined conditions, severities, and pass/fail criteria. The tests are intended to be run on a "once-off" basis to prove any product's ability to satisfy the performance standard's requirements. This second edition cancels and replaces the first edition published in 2009 and constitutes a technical revision. The significant technical changes with respect to the previous edition include the introduction of the performance standards for 10 Gbit/s 850-nm wavelength, vertical cavity surface emitting laser (VCSEL) devices and the deletion of the package diagrams and pin configurations in Clause A.4 and Clause B.4 by citing the VCSEL package standard IEC 62148-15 instead.Keywords: 850-nm discrete vertical cavity surface emitting laser (VCSEL) devices, transverse multimode types