Asynchronous transfer mode (ATM) system having an ATM device coupled to multiple physical layer devices

DETAILED DESCRIPTION What is claimed is: 1.
An asynchronous transfer mode (ATM) system comprising: an asynchronous transfer mode (ATM) layer device, the ATM layer device having both a plurality of terminals for receiving a transmit bus which has a plurality of transmit conductors and a plurality of terminals for receiving a receive bus which has a plurality of receive conductors; a first physical (PHY) layer device having both a plurality of transmit terminals coupled to the transmit bus for communicating with the ATM layer device through the plurality of transmit conductors and a plurality of receive terminals coupled to the receive bus for communicating with ATM layer device via the plurality of receive conductors; a second physical (PHY) layer device having both a plurality of transmit terminals coupled to the transmit bus for communicating with the ATM layer device through the plurality of transmit conductors and a plurality of receive terminals coupled to the receive bus for communicating with ATM layer device via the plurality of receive conductors; wherein incoming data cells are routed from at least one of the first or second PHY layer devices to the ATM layer device then from the ATM device to a switching device; and wherein outgoing data cells are routed from the switching device to the ATM layer device then from the ATM layer device to at least one of the first or second PHY layers.
2.
The ATM system of claim 1 wherein one of either the first physical (PHY) layer device or the second physical (PHY) layer device is selected for communication with the ATM layer device by a control signal communicated between the ATM layer device and the first and second PHY layer devices.
3.
The ATM system of claim 1 wherein the first and second PHY layer devices are coupled together in a serial manner via a serial conductor, the serial conductor being used to arbitrate which PHY layer device gains access to the receive bus.
4.
The ATM system of claim 1 wherein the first and second PHY layer devices time multiplex the use of the receive bus via a control signal communicated between the first and second PHY layer devices and the ATM layer device