Flashlink time division multiplexers multiplex asynchronous SD and HD-SDI signals into fully compliant SMPTE HD- or 3G-SDI. By multiplexing into a fully compliant SMPTE HD or 3G-SDI, the signal can be transported through standard 3G/HD-SDI infrastructure like routers and optical converters, enabling full utilization of the HD- or 3G-SDI link. A two-module combination makes it possible to transport eight SD-SDI or ASI signals over a 3G-SDI link with onboard optics.