US Patent #5,450,404
Explicit and Implicit Token Media Access Protocol
with Multi-Level Bus Arbitration
ABSTRACT
Primary implicit token slots (that is, token slots following a message or jam used to restart network activity) are assigned to multiple transceivers. When a transceiver assigned to a shared slot has data to transmit, it emits a jamming signal instead of a message in its token slot. This jamming signal serves as a synchronization for a second implicit token slot progression in which only transceivers sharing the primary level implicit token slot participate.
Phil Koopman -- koopman@cmu.edu