Thanks to this more complex trunk circuit, outgoing trunks are selected by a quicker and more versatile method than the sleeve test previously used. Each trunk circuit provides a ground on an FT lead to indicate idleness. The FT leads for trunks in a particular group are cross-connected to a FTC (frame test common) lead for its trunk link frame, to indicate that the TLF has one or more idle trunks in that group. The route relay in the completing marker connects sensor relays to all the trunk link frames, allowing the marker to choose a TLF that has an idle trunk and then connect to that trunk through the trunk link connector (TLC) to choose one of those idle trunks. This two step method, along with the mixing of incoming and outgoing traffic, distributed traffic more evenly, thus alleviating the link congestion problems that often arose with earlier methods that restricted a trunk group to one or two outgoing switch frames.