Abstract: An automated main distributing frame system comprises a multistage network with each stage including passive switches on which cross connections are made by shared, automated actuators under computer control to thereby provide paths through the network. Test access can be provided through the actuators to both switched and nonswitched lines. The switches are arranged in modules so that the system can be expanded from a small initial size to an ultimate capacity as the need arises by the addition of switch modules without any retermination of existing connections. In some network configurations the system provides for rearrangements to eliminate first trial blocking of desired connections.