The PC104P-SIO4B is a four channel full-duplex RS-422/485 serial board. Each channel can operate up to 10Mbits/s. Up to 32 Kbytes of FIFO buffering for both transmit and receive (256 Kbytes Total FIFOs) data on each channel provides for a smooth and efficient interface between the serial interfaces and the host computer. This product is based on the Zilog® Z16C30® high speed Integrated Universal Serial Controller (USC) which supports Asynchronous, Isochronous, Bisync, Monosync, HDLC, SDLC, External Sync and Nine-Bit protocols. The USC chip provides full duplex operation with baud rate generators, digital phase-locked loop for clock recovery and a full duplex DMA interface.