OXE network of 30 nodes (R9, R9.1 nd R10) is build around two central nodes (node1 and node2). A new system is connected to node1. It can receive calls from all net nodes, it can call all nodes attached to node1, it can call node2, but any attempt to call a use who belongs to systems attached to node2, gets immediate a continuous noise. The other side is ringing, but the line is silent (no voice).