The SeaI/O-530 and SeaI/O-540 digital I/O modules provide open-collector outputs and optically-isolated inputs for distributed-control tasks. The SeaI/O-540's packs 32 open-collector outputs while the SeaI/O-530 combines 16 optically isolated inputs with 16 open collector outputs. Non-polarized inputs can monitor 5 to 30 Vdc and provide optical isolation to protect the host computer from voltage transients and ground loops. For connecting I/O, removable terminal blocks are standard on both modules. Pricing for the SeaI/O-530 starts at $359 while the SeaI/O-540 series starts at $379. SEALEVEL SYSTEMS INC., Liberty, SC. (864) 843-4343.