A fully-electronic high-speed transmission with a highly-integrated set of quadrature direct-conversion TX and RX modules in 130nm SiGe HBT technology operating in the 240 GHz transmission window is presented. In view of high packaging costs of the currently available THz communication front-ends, each of the modules is implemented as a single chip with a broadband silicon lens-integrated on-chip antenna and assembled on a low-cost high-speed PCB providing an IF operation bandwidth of 13 GHz at the board-connector level. For the preliminary wireless-link tests at a distance of 1m, a 30 Gbps and a 50 Gbps transmission speed with EVM of 26% and 29% is demonstrated for BPSK and QPSK modulation, respectively, with no channel equalization applied.