Power-over-LAN standard imminent

Today we’d like to look at how recent advances will help supply electrical power over an Ethernet LAN.

To get the latest, we talked with Amir Lehr, vice president of marketing and strategic planning at PowerDsine. Amir works with the IEEE task force working to standardize an approach for passing power over Ethernet. The 802.3af task force is run under the auspices of the 802.3 workgroup, the same group that developed the original Ethernet specification.

Amir reports that the final version of the 802.3af spec is complete, and ratification is expected this month. The companies working together for ratification and implementation include PowerDsine, Siemens, 3Com, Nortel, Proxim, Avaya, Cisco, Alcatel, Mitel, Intel and Symbol Technologies.

Today, approximately 85% of the available IP phones and wireless LAN access points receive power from the RJ-45 data connector. These powered terminals, however, are still proprietary, with a migration to the final 802.3af standard planned. Deployment of the final standard will assure compatibility between the Ethernet power sourcing equipment and powered terminals.

In addition to providing an uninterrupted power source for IP phones, this power can also be used to run other devices. For example, the Gibson electrical guitar has an Ethernet connection used for digital recording; the same connector can power the guitar. PDAs and LAN-attached security cameras can also get their power from Ethernet.

In the near future, 802.3af could also be applied to power PCs. The standard provides for 12.95 watts of power to the Ethernet port. Today’s PCs take between 26 watts and 42 watts in some modes, with some PC consuming as little as 15 watts. PC and PC chip manufacturers like Intel are working to lower power consumption – so once they reach the power range available on Ethernet, users could eliminate the need for separate power supplies and cables.