The Jade SPIO Serial/Parallel/Intemipt Controller board was an IEEE S-100
standard multi-user communications board designed around the Zilog Z80
peripheral chip line. It featured two Z80-SIO Serial I/O controllers, up to
four Z80-CTC Counter/Timer chips, and a Z80-PIO Parallel I/O controller
chip. It was am extremely useful and powerful serial I/O board.
The manual for this board can be obtained
here.