Abstract: A system and method for operating, at a near location, a safety-critical device 260 located at a remote location. The system comprises a first control panel interface 200 and at least one operating input device 220 at a near location, adapted for transmitting control signals to the safety-critical device 260 at a remote location. The first control panel interface 200 comprises hardware barrier communication means 206 and at least a first and a second hardware safety barrier 202, 204, each with safety barrier interfaces connected to the at least one operating input device 220 and to the hardware barrier communication means 206 for communication through the non-secure network 240. The system further comprises a second control panel interface 250, connected to the safety-critical device at the remote location, adapted for receiving control signals from the first control panel interface 210 via a secure communication tunnel 242.

Abstract: A system and method for operating, at a near location, a safety-critical device located at a far location. The system includes a first operating input device to be operated at the near location, providing a first barrier control signal; and a second operating input device to be operated at the near location, providing a second barrier control signal. The first barrier control signal is communicatively connected to a near end of a first secure communication tunnel through the non-secure communication network, and the second barrier control signal is communicatively connected to a near end of a second secure communication tunnel through the non-secure communication network. A far end of the first secure communication tunnel is communicatively connected to an activating input of a first barrier circuit, and a far end of the second secure communication tunnel is communicatively connected to an activating input of a second barrier circuit.

Abstract: A system and method for operating, at a near location, a safety-critical device located at a far location. The system includes a first operating input device to be operated at the near location, providing a first barrier control signal; and a second operating input device to be operated at the near location, providing a second barrier control signal. The first barrier control signal is communicatively connected to a near end of a first secure communication tunnel through the non-secure communication network, and the second barrier control signal is communicatively connected to a near end of a second secure communication tunnel through the non-secure communication network. A far end of the first secure communication tunnel is communicatively connected to an activating input of a first barrier circuit, and a far end of the second secure communication tunnel is communicatively connected to an activating input of a second barrier circuit.

Abstract: In a system and method for operating, at a near location, a remote safety-critical device, the system includes a first operating input device operated at the near location, providing a first barrier control signal; and a second operating input device to be operated at the near location, providing a second barrier control signal. The first barrier control signal is communicatively connected to a near end of a first secure communication tunnel, and the second barrier control signal is communicatively connected to a near end of a second secure communication tunnel, both through the non-secure communication network. Far ends of the first and second secure communication tunnels are communicatively connected to activating inputs of first and second barrier circuits, respectively. The first and second barrier circuits enable operation of the safety-critical device when both are activated.

Abstract: The present invention discloses a method and an arrangement providing transmission of data through a node, e.g. a switch, having different input and output line interfaces in a wide range of data speed, without introducing any loss of bits, but still maintaining the nominal bit rate. This is achieved by means of a very simple and flexible implementation. At the receiving side of the switch, one extra bit per frame is transferred over the time slot bus of the switch if the number of bits in the corresponding FIFO of the input line exceeds a predefined upper limit. In contrast, one bit less per frame is transferred if the number of bits in the corresponding FIFO of the input line goes below a predefined lower limit. At the transmitting side of the switch, a FLL circuit regulates the data rate out of the FIFOs. The FLL circuit is implemented as a P-regulator having i.a. the fill degree of the FIFO as a direct input.

Abstract: A method and an arrangment for reducing phase jumps in a frame synchronization signal when switching between synchronization signal when switching between synchronization reference sources are disclosed. A new reference signal to which each of the two reference sources (signals) are phase locked, and has frequency n times the respective reference signal, is generated. A selection signal selects the new reference signal to be used, and the selected one is then divided back to its original frequency creating an input signal to a phase-locked loop generating the resulting frame synchronization signal. In this way, the maximum phase jumps are reduced from one period of the original reference signals to one period of the new reference signal. The invention is particularly applicable for reducing phase jumps on a master frame synchronization signal in a PDH system.