Abstract: Data transmission system based upon the Internet protocol (IP) comprising a private transmission network (18) and a public transmission network or the like (16) interconnected by a network address translation device NAT (12) wherein at least a workstation WS (10) connected to said private transmission network has to establish a communication with a peer device (14) connected to the public transmission network, the local IP address of each data packet from the workstation WS being translated into a NAT address used to provide the route through the public transmission network. The system includes a registration server (19) connected to the public transmission network for registering the local IP address corresponding to the NAT address and providing the correspondence between the NAT address and the local IP address to the peer device in order for this one to replace in the IP header of each data packet received by the peer device, the NAT address by the local IP address.

Abstract: Data transmission system based upon the Internet protocol (IP) comprising a private transmission network (18) and a public transmission network or the like (16) interconnected by a network address translation device NAT (12) wherein at least a workstation WS (10) connected to said private transmission network has to establish a communication with a peer device (14) connected to the public transmission network, the local IP address of each data packet from the workstation WS being translated into a NAT address used to provide the route through the public transmission network. The system includes a registration server (19) connected to the public transmission network for registering the local IP address corresponding to the NAT address and providing the correspondence between the NAT address and the local IP address to the peer device in order for this one to replace in the IP header of each data packet received by the peer device, the NAT address by the local IP address.

Abstract: A device positionable in a borehole for determining rock mass deformability, comprises a generally cylindrical body having at least one pair of diametrically opposed, elongated expandable wall portions for pressure contact engagement with the borehole wall, the wall portions being radially outwardly expandable in diametrically opposite directions along a predetermined axis extending transversely to the longitudinal axis of the borehole. An elongated core is arranged in the body and extends longitudinally thereof. A chamber is associated with a respective one of the expandable wall portions and is defined between the respective expandable wall portion and the core, the chambers associated with the at least one pair of expandable wall portions being in fluid communication for receiving a fluid under pressure.