同步串行总线接口，可提供最大10Mbits/s的传输速率。支持HDLC, X.25 LAP B, ISDN LAP D, SDLC, ASYNC, and BISYNC协议。

Features

• High speed synchronous / asynchronous, full duplex, RS-422 / RS-485 ports
• Universal cPCI (PICMG 2.0 Rev 2.1) adapter operates in both 5V and 3.3V PCI slots.This flexibility allows for a single serial interface board to be used across a wide range ofdifferent types of computers including both current and future computing systems.
• Each port has independent clock generators allowing each to operate at completelydifferent baud rates.
• Each port can be operated in True-Asynchronous mode utilizing the two on board16C950 UARTS. When in True-Asynchronous mode, the ports can be operated just likea standard serial (COM) port. See the True-Asynchronous section for more details.
• Automatic RS-485 handling (e.g. tri-state the driver when idle)
• Receive echo cancel. Disables the line receiver during transmits to prevent receiving thedata that is transmitted in 2-wire 485 modes.
• Transmit and Receive status LED’s for each port.
• On board RS-485 termination network for each receive signal pair
  100 Ω termination
  1 kΩ biasing resistors (pull-up and pull-down)