● Both bus and tree topologies are characterized by the use of multipoint  （71）  . For the bus, all stations attach, through appropriate hardware  （72）  known as a tap, directly to a linear transmission medium, or bus. Full-duplex operation between the station and the tap allows data to be transmitted onto the bus and received from the  （73）  . A transmission from any station propagates the length of the medium in both directions and can be received by all other  （74）  . At each end of the bus is a  （75）  , which absorbs any signal, removing it from the bus.