Abstract: A communications network comprising a hierarchy of communications systems all operating within the constraints of token ring protocols and operationally defining a single shared token ring. At least one of said systems is formed by a token ring hub as disclosed and claimed in our copending application 177,764 and is connected into a system comprising the next higher hierarchal level which may be another such token ring hub or a token ring LAN system. Each said hub has means for receiving a signal which indicates that the standard token ring protocols are satisfied with respect to the direct connection of the hub of a computer having a token ring adapter card fitted, or indicative of such a computer connected to another said hub at a lower level of the hierarchy.

Abstract: In a communications network, a portable token ring hub which serves as a computer communications network for a plurality of computers and answers to the protocol requirements of the computer adapter cards configured to a token ring topology and which also serves as an expander with respect to an installed token ring LAN. The hub comprises a plurality of input/output ports including respective sockets into each of which an adapter card of a respective computer plugs, a trunk insertion unit having an outlet port to which a wander lead and a trunk coupling device plug are connected, and an internal token ring which is normally a closed ring but into which each of the said input/output ports and the outlet port are inserted by means of relay contacts in accordance with the requirements of the token ring protocol.