The PMC66-SI04BXR board is a four channel serial interface card which provides high speed, full-duplex, multi-protocol serial capability for PMC applications with Rear I/O . The SIO4BXR combines two multi-protocol Dual Universal Serial Controllers (USC®), 8 external FIFOs, and multi-protocol transceivers to provide four fully independent asynchronous or synchronous serial channels. Multiprotocol Transceivers support RS422 (V.11)/RS485, RS423 (V.10), RS232 (V.28), RS530, as well as other Mixed Protocol modes. These features, along with a high performance PCI interface engine, give the PMC-SIO4BXR unsurpassed performance in a serial interface card.