Remotely located access systems where there is no Ethernet (TCP/IP protocol) around can be controlled via phone line (analog / ISDN / mobile phone). PC and remote RS485 bus are each connected to a modem. Additional remote subsystems can be accessed in the same way, as long as each has its own distinctive phone number. If an Ethernet is available, then modem and modem interface are replaced by the Ethernet interface box
Remote-Operation: The remote modules are controlled via a modem
