B&B Electronics USO9ML2 USB to RS232 Converter

B&B Electronics ULinx USO9ML2 USB to RS-232 Converter is an isolated USB-to-serial adapter that provides two RS-232 DB9 male ports (DTE) from a single USB connection, enabling legacy devices to connect to modern computers or controllers. It delivers 2000 V of port-to-port isolation to protect equipment from surges and ground loops, supports RS-232 data rates up to 460.8 kbps (USB side operates at 12 Mbps), and employs a USB interface that can be powered from the USB bus (5 V) or from an external 10–30 VDC supply. The 2-port USO9ML2 variant typically consumes about 3 W, while the 4-port variant consumes around 5 W when an external supply is used. Its enclosure measures 6.5 × 1.2 × 3.1 inches without flanges (7.5 × 1.2 × 3.1 inches with flanges), and it is rated for operating temperatures from 0 to 70 °C with 0–95% non-condensing humidity. Regulatory approvals include FCC, CE, and UL, reflecting its suitability for industrial environments. The device remains compatible with USB 1.1 and 2.0 and preserves standard RS-232 signaling, making it a robust bridge between modern hosts and legacy serial equipment that requires isolated operation.