Apparatus and method for implementing a suspend mode in an ethernet-based communications system

Abstract

The present invention describes a communications system having a first link partner and a second link partner that are connected by a communications link having at least four pairs of conductors. According to IEEE Standard 802.3 (e.g. Ethernet) for 1000Base-T, a data link is maintained (in a period absent data transmission) by sending idle signals over four pairs of conductors of the cable to maintain a logical connection. This idle signal scheme is replaced with an alternate idle signaling scheme that uses only two pairs of conductors to maintain a logical connection and therefore can operate with using lower power. The other two pairs of conductors of the four pairs of conductors are unused to maintain a logical connection absent data transfer, and therefore can be used to implement a Suspend Mode of operation. During Suspend Mode, the physical layer of each link partner powers down unnecessary circuitry so as to operate in a low power environment. To initiate the Suspend Mode, idle signals are sent on one of the un-used pairs of the conductors mentioned above. To exit Suspend mode, idle signals are sent on respective conductors simultaneously.