Abstract: The architecture of VIOP (vital input/output platform) is introduced briefly. Some key technologies are introduced, including dual-system redundant VIOP system interface, module composition, internal-external communication connection status, time-sharing acquisition principle of the same relay node states realized through VIOP dual-system hot-standby AM (acquisition module), and dual-break drive principle realized through dual-system hot-standby DM (drive module). The whole redundant network architecture of VIOP and VIOP diagnostic maintenance function are briefly introduced. Then the application of iLOCK-200T switch controller with VIOP in SmarTram signaling system of Shenzhen Longhua Modern Tram Demonstration Line project is emphatically introduced. The architecture configuration and working principle of one main logic unit with multiple VIOP at Longhua Modern Tram Dahe Station are described. The technical scheme of the next VIOP iteration is prospected. It is pointed out that the cost can be reduced by remote updating and network communication remote deployment in the future, realizing simple and efficient control of switch controller.