Patent ID: 6128299
Filing Date: 2000-10-03
Classification: H04L,H04Q

Abstract:
A communication system for connecting peripherals to an ATM network, comprising:a plurality of peripheral devices interconnected in series by a communication link; anda switch connecting the communication link to the ATM network, the communication link beginning and terminating at the switch so as to form a ring, such that cells transmitted by any of the plurality of peripheral devices are further transmitted by the switch onto the ATM network;each peripheral device comprising an input port for receiving data and an output port for transmitting data;the switch comprising a duplex switch port having an input connection for receiving data and an output connection for transmitting data;the output connection being connected via the communication link to the input port of the first of the plurality of peripheral devices;each input port of each of the other peripheral devices being connected via the communication link to the output port of the previous peripheral device;the output port of the last peripheral device being connected via the communication link to the input connection of the duplex switch port;wherein each of the plurality of peripheral devices transmits data received at its input port on its output port, such that data progresses around the communication link to be received at the switch;a token cell being transmitted by the switch onto the communication link and, thereafter, being forwarded in turn by each of the plurality of peripheral devices back to the switch;each peripheral device having data to send transmitting a cell on its output port after receiving the token cell on its input port;and wherein at least one peripheral device, after receiving the token cell on its input port, transmits the token cell on its output port, transmits the cells transmitted by previous peripheral devices, and then transmits its own cell if it has data to send, such that a cell chain is created which is received by the switch via the communication link;at least one peripheral device having data to send transmitting its own cell after detecting an idle character following the token cell.