This Card permitted the ICL System 25 Mini-Computer to support up to 16 RS232 Asynchronous Serial Devices per Card. The System 25 card cage could house about 10+ I/O Cards.
One customer had at least 8 of my NL90 Cards installed in one of their System 25 computers. This supported up to 120 simultaneous remote users located all around Australia. They were connected to my cards via Scitex Statistical Multiplexers over dedicated leased 9600 baud Telecom lines. These Users were in addition to the many (some 30+) simultaneous local users located within the building.
I hand designed/routed the FPGA using the Xilinx Software.