PowerDsine adds midspan juice to PoE

Power-over-Ethernet specialist PowerDsine has launched a pre-standard range of high-power 'midspans' - boxes which sit in front of a non-PoE switch and add up to 32W to the cable for powering devices at the far end.

"Moving to higher power opens up a lot of new applications for us - tilt, pan and zoom cameras, 802.11n wireless access points, IP videophones and even thin clients," said Graham Howton, PowerDsine's sales boss for northern Europe.

The new Gigabit-capable midspans anticipate the upcoming 802.11at standard for PoE, expected to be ratified by early 2009. The new spec will approximately double PoE's maximum capacity from the 15.4W of today's 802.11af standard.

Midspans sit in front of switches and are designed as a simple and cheap way to add PoE to an existing network. PoE then means that you don't need to go to the expense of installing mains sockets everywhere you want to install a webcam or IP phone, for instance.

Howton claimed that, although the new PD-7000G family is pre-standard, the specification is close enough to ratification that the boxes may not even need a firmware upgrade to meet the final version.

He added that PowerDsine, which owns some of the patents behind Power-over-Ethernet and also supplies PoE chips to other equipment manufacturers, was closely involved with developing the spec.

For now, there are no 802.11at devices out there, so as well as six, 12 and 24-port midspans, PowerDsine also announced single-port splitters. These break out the power at the far end, delivering the remote device with Ethernet and a DC voltage on separate cables.

Howton said that with a 24-port midspan at $1,500 (£770) and the splitters at $69 (£35), 32W PoE can be added to a network for around £70 per powered device. He added that as the midspans also include power management on each port, they can also be used for energy management and access control, for example turning off remote devices out of working hours.

The new midspans can drive power over up to 200m of Cat5, Cat5e or Cat6 cable, and can also power current 802.11af PoE gear - they sense how much power the remote device needs and adapt accordingly.

Other vendors too are lining up pre-standard 32W PoE products. For example, Foundry Networks said it will ship what it called PoE Plus modules for its FastIron enterprise switches this summer.

"We have very high confidence that our draft version will meet the spec - that confidence comes from the chip vendors," asserted Bob Schiff, who runs Foundry enterprise business unit. "The current Draft 3 is far enough along that we can accommodate any change in firmware."

Schiff said the challenge is that network devices' demands have been outstripping the power available from 802.11af PoE.

For instance, an 802.11n wireless access point restricted to 15.4W "may be able to run in three-by-three [antenna] mode, but probably not in full four-by-four, so it will have lower range," he added.

Graham Howton added that there is even more powerful PoE to come, with PowerDsine's engineers testing variants capable of delivering 64W or more. These use all four cable pairs instead of today's two pairs, and could drive a laptop or even a low-power desktop PC, he suggested.