open 34 command was generated by the workstation token ring adapter and sent to the mau this signal provides the energy to activate the relay in the mau that places the node actively into the network instead in the present invention the dc voltage variation from a workstation is detected by the dc detection unit 34 and is conveyed to the processor 28 via common bus 36 the dc variation in this case represents a soft request to the network controller 10 for changing the network configuration so that the workstation is entered into the common ring the dc variation is used by the workstation in two instances first the workstation uses it initially to enter the common ring second after the workstation has been taken of the common ring it generates the dc offset to re enter the common ring as it has no other method of communicating with the network controller 10 in the particular embodiment the 5 vdc signal from the workstation adapter is detected by the dc detection unit 34 conveyed to the processor 28 and interpreted as a request from the workstation to be placed back into the primary common ring in operation the network controller 10 detects via dc detection unit 34 5 vdc offset signals on the workstation transmit lan lines of those workstations wishing to enter the common.