This paper presents the construction and measurement of a phased array BPSK transmitter system operating at 246 GHz with tested data rates of up to 32 Gbit s-1. The system is built using custom monolithic microwave integrated circuit (MMIC) and a novel packaging solution. The construction showcases the flexibility in the chosen approach, paving a path for future systems. It is the first TX array with significant beam steering capabilities tested above a pure antenna pattern stage above 200 GHz. The system is tested for realistic usage scenarios. Bit-error-rate (BER) measurements are used to showcase real-world usability. BER over angle and BER over steering angle are measured to verify the operation of the transmitter.