Power Electronics

Interoperability Lab Begins Multivendor PoE Testing


By Ashok Bindra, Editor, PETech

Interoperability Lab Begins Multivendor PoE Testing

Early this month, several members of power over Ethernet (PoE) consortium participated in a group test period at the University of New Hampshire’s InterOperability Laboratory (UNH-IOL). Engineers from these participating companies, which included Avaya, Cisco Systems, 3COM, Linear Technology, PowerDsine, and Texas Instruments (TI), along with student engineers, executed the PoE Consortium’s IEEE 802.3af tests.

In essence, the interoperability testing was performed on a complete matrix of powered devices (PDs) and power sourcing equipment (PSE). Primarily, the focus was on physical layer testing for these two product groups. On the PSE side, detection, classification, and power application functions of the device under test (DUT) were examined. According to test engineer Jeremy Kent of UNH-IOL, the unit is tested to ensure that it sends out proper detection and optional sequences, and falls within the constraints of the standard with regards to pulse timing, voltage and current levels, and noise levels. In addition, several other power supply output parameters are outlined in the PSE test suite.

On the PD end, the unit was tested to see if it presents a valid detection signature when it is requesting power over the interface and that it provides classification information about its power requirements to the attached PSE. Furthermore, tests were done to see if the PD under test becomes operational after it receives power.

”We put each PSE and PD pair in a real world environment, attached over a 100 m cable. Power is applied to the link segment, and data is exchanged between the two devices to ensure data integrity and operation,” said Kent.

PowerDsine, for instance, tested its Power over LAN Dual In-line Memory Module (PoL-DIMM) technology, which is based on its embedded IEEE 802.3af-compliant Power over LAN ASIC. It also tested its Power over LAN 3000 series of midspans. In addition, TI’s power interface switch TPS2370 and power sourcing equipment manager TPS2383 were tested for interoperability.

PoE Consortium Manager Gerard Nadeau said, “Parametric testing has improved extensively since the last GTP and will continue to advance. Feedback from members participating in the test event will be used to further develop our test procedures and test suites. As a result of this GTP, the number of powered devices in the consortium’s test bed has more than doubled, resulting in a more comprehensive matrix of interoperability testing.”

The UNH-IOL continues to look for new members to expand its interoperability test bed. Another Power over Ethernet GTP will be held later this year.

For more information, visit www.iol.unh.edu/consortiums.

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