VME-SIO4A is a four channel RS422/RS485 or RS232 serial board. Each channel can operate up to the maximum 10 Mbits/ sec. An optional FIFO buffer (up to 32 Kbytes) for both transmit and receive data on each channel provides for a smooth and efficient interface between the serial interfaces and the VME host processor. The board is based on the Zilogª Z16C30 high speed Integrated Universal Serial Controller (USC) which supports Asynchronous, Isochronous, Bisync, HDLC, SDLC and Nine-Bit protocols. The USC chip provides full duplex operation with baud rate generators, digital phase-locked loop for clock recovery.