Surveillance zone remote surveillance method having zone/centre digital word interface links with bridge assembly links virtual circuit/platform connected detecting digital word transmission loss

摘要

The remote surveillance system has a subscriber network (10) and a packet switching network (12). There are two control platforms (18) forming a digital word communications interface between the surveillance zone and the remote surveillance area. Virtual networks relay frames using the X25 protocol. There is an assembly of bridge links connected between the virtual circuit and the platform, detecting the loss of digital word transmission.