B&B Electronics 4WSD9OTB Isolated DC Converter

BB-4WSD9OTB is an isolated RS-232 to RS-422/RS-485 in-line converter that provides up to 2 kV isolation between the RS-232 input and the RS-422/RS-485 output. It is DC-powered (10–48 VDC) via a 2‑position terminal block and typically draws about 28 mA at 12 VDC. The RS-232 side uses a female DB9 connector (DB9F), while the RS-422/RS-485 signals are delivered over a 5‑position data terminal block. Its compact footprint measures roughly 3.9 x 1.7 x 0.9 inches (9.8 x 4.3 x 2.3 cm), and it operates from 0 to 70°C (32–158°F). The unit carries CE approvals and is designed to bridge legacy RS-232 devices to differential serial networks, enabling reliable long-distance or electrically noisy installations without compromising equipment safety.