Horner Engineering India Pvt. Ltd. Offers Expandable Stackable I/O System for Operating Control Stations. Horner Engineering India Pvt. Ltd. Is the manufacturer of industrial automation and custom solutions for the global market. Expandable Stackable I/O System for Operating Control Station`s modules are snapped onto the Operator Control Station [OCS] or an off-mounted base, and then stacked onto each other. Expandable Stackable I/O System for Operating Control Station`s modules is encased in metal housings and meets stringent noise, vibration, and shock standards. A maximum of 4 modules can be stacked directly onto an OCS, and another 20 modules can be added by using the fibre optic FOX I/O System.