Apparatus for and method of detection of powered devices over a network
US7564904B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 2006 |
| Grant date | Jul 21, 2009 |
| Priority date | — |
| Expiry date | Oct 21, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L43/50
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A novel mechanism for detecting the presence of powered devices over a network. A unique, infinite pseudo-random sequence of pulses are generated and transmitted over the network to the link partner attached to the other end of the cable. At each time unit, the PSE decides whether or not to transmit a pulse at that time. Thus, the pulses generated have pseudo-random inter-pulse delays between them. In addition, each pulse is pseudo-randomly selected to have either positive or negative polarity. If the link partner is a powered device it will be in loopback mode and the transmitted pulses will be looped back to the transmitter (i.e. the PSE). The PSE, at each time unit regardless of whether or not a pulse was transmitted, opens a search window in which it listens to the RX line for the appropriate expected behavior. If a pulse was transmitted, the PSE expects to see a pulse looped back. Similarly, if no pulse was transmitted, the PSE does not expect to receive a signal during the search window. If the expected behavior is observed, a match counter is incremented, otherwise a mismatch counter is incremented. If a sufficient number of matches are received, the PSE concludes that a pow…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.