Need USB 2.0 to Synchronous/Asynchronous Serial Networking Capabilities?

The FarSync Flex USB Sync/Async Adapter works with X.21, RS530, V.35, RS449, RS485 and RS232C network interfaces operating at serial line speeds up to 2 Mbits/s. FarSync Flex USB provides as single port and is designed to provide a high performance communications solution for use with TCP/IP and an API for companies who wish to quickly develop their own communications solutions. The API permits HDLC framed and transparent bit stream operation from Linux and Windows. The FarSync Flex software and drivers on Windows and Linux can now support 2 wire RS485 operation. All existing FarSync Flex devices can be upgraded to support RS485. This new RS485 serial support adds line types of 2 wire (half duplex) RS485; multi drop and single ended, with line speeds of up to 512 Kbits/s, and with NRZI, FM1 or FM0 signaling modes.

F-FS4100 FarSync Flex USB Sync/Async Adapter with Linux and Windows Drivers