B&B Electronics BB2251 RS-232 to RS-485/422 Serial Converter

The B&B Electronics BB2251 is a compact, reliable RS-232 to RS-485/422 serial interface converter designed for industrial and commercial data communication applications. It allows seamless integration between RS-232 serial devices and RS-485 or RS-422 multi-drop networks, extending communication distances and enabling multi-device bus configurations.

Key Features:

• Converts RS-232 signals to RS-485 (2-wire) or RS-422 (4-wire) formats
• Supports data rates up to 115.2 Kbps
• Automatic send data (ASD) control for half-duplex RS-485 operation — no handshaking lines required
• Extends communication distances up to 4,000 feet over RS-485/422
• DB9 male RS-232 connector for direct PC or device connection
• Screw terminal connections on the RS-485/422 side for reliable field wiring
• Powered directly from the RS-232 port — no external power supply required
• Wide operating temperature range suitable for industrial environments
• Compact form factor for easy installation in tight spaces

The BB2251 is ideal for connecting PCs, PLCs, HMIs, and other RS-232-equipped devices to industrial RS-485 networks such as Modbus RTU, DMX512, and other multi-drop serial bus protocols. Its plug-and-play design requires no configuration switches, making installation fast and straightforward.