Teridian Semiconductor Corporation

Michael Nootbaar

Andrew Mills

Ralph Andersson

David Rosky

Michael Behrin

Anthony Worsham

A method for maintaining the states of a receiver during the silent line state of a network device operating in a low power link suspend mode is presented. Accordingly, a method of freezing the states of the equalizer and keeping the receiver clock locked to a frequency that is approximately equal to that of the input data while providing for rapid adjustment to the phase and thus recovery of the input data is presented. During Silent Line State (SLS), the receiver states are frozen using methods that avoid parasitic decay. Also, the receive clock phase lock loop is locked onto the local transmit clock since the local transmit clock has a frequency approximating the incoming data frequency. During the SLS, the transmitter of the remote network device may have been turned off to conserve power therefore the receiver has no way of immediately knowing the phase of an incoming data. Thus, in order to prevent loss of data, the receiver loops of the receiving network device are trained to the frequency of the transmitting remote network device using periodic Link Suspend packets. Thus, in most cases, only the phase of the incoming signal need be acquired when data arrives. The phase may be quickly acquired using loop bandwidth shift methods whereby the receive clock phase lock loop bandwidth is increased to a value that aids rapid acquisition of the input clock and then, after acquisition, the bandwidth is shifted to a low value to enhance noise rejection during tracking.

Apparatus and method for freezing the states of a receiver during silent line state operation of a network device

A method and apparatus for handling data during link suspend pulse and the silent line state of a network device operating in a low power link suspend mode is presented. Accordingly, a new generation of network devices capable of operating in both the full power operational mode of prior art network devices, and a low power 'link-suspend' operational mode are presented. The low power 'link-suspend' (LS) mode reduces the power consumption of a LAN communications link at the physical layer by eliminating the need to continuously transmit standard idles to maintain link between two linked partners. In the LS mode, a low duty cycle &#x201c;link-suspend-packet&#x201d; (LSP) is transmitted between periods of silent line state (SLS). During the SLS, which is a non-data transmission period, the transmitter may be turned off to conserve power therefore preventing the receiver from immediately knowing the phase of an incoming data. Thus, in order to prevent loss of data, the LSPs serve to maintain link and provide information necessary to train the receiver loops so that they can quickly lock onto the incoming data. LSPs are specially constructed so that they can serve as part of the data preamble when the network devices are operating in the link suspend mode. Therefore, the nature of the LSPs is that they are compatible with the standard protocol requirements for data transmission.

Method and apparatus for handling link suspend pulse and silent line state transitions of a network device

The invention provides a method for initializing a link suspend device for optimum receive recovery. A method for negotiating link parameters to facilitate rapid recovery of the input data from a silent line state is described. The invention can be applied to network devices in point-to-point data communications links capable of operating in a low power link suspend mode.

Method for initializing a link suspend device for optimum receive recovery

A method and apparatus for transparent implementation of link-suspend capabilities in network devices is presented, which is capable of operating in full or substantially full power operational mode, as well as in a low power 'link-suspend' operational mode. The low power 'link-suspend' (LS) mode reduces the power consumption of a LAN communications link at the physical layer by eliminating the need to transmit continuous standard idles to maintain link between two linked partners. In the LS mode, a low duty cycle &#x201c;link-suspend-packet&#x201d; (LSP) is transmitted between periods of silent line state (SLS). During the SLS, which is a non-data transmission period, the transmitter may be turned off to conserve power. The transmitter power is turned back on when it is time to transmit LSPs or data.

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Sun City, CA, United States of America

Michael Nootbaar