Abstract: An arrangement for testing relay contacts of a signal distributor is disclosed. The output relay contacts are coupled via isolation diodes to a common circuit node and the input relay contacts are coupled to a second node. A potential is applied to the first node through the diodes and contacts to a single scan point and selective operation of each distributor relay can be verified at the scan point. By reversing the nodes, the integrity of the diodes can be checked. Make, break, and transfer contacts are tested.

Abstract: An automatic message billing arrangement for use with a telephone system is disclosed. The billing arrangement monitors the trunks to ascertain when a trunk is seized for service. In response to a trunk being seized, the common control markers, which establish connections between the lines and trunks, are interrogated to determine which marker has seized the detected trunk. When the marker is found, the identity of the calling line to be connected to the trunk is ascertained from the marker. The calling line identity and trunk identity are used in recording the initial billing entry.