PoE PD Modules-Maintain PoE Power
Signature in Dual WAN Device
August, 2013
How to Maintain PoE Power Signature in Dual WAN
Device
A. Scope
This document can be applied on Befact PoE / PoE+ PD modules. Current models of
Befact PoE/PoE+ PD modules are TPD modules (TPD-12, TPD-50, TPD-33), SPD
modules (SPD-12, SPD-50), THPD modules (THPD-12, THPD-50, THPD-33), AHPD
Module (AHPD-12).
B. Case Study
To Maintain Power Signature (MPS) can force WAN 2 PoE link to keep active when the
default power source is coming from WAN 1 PoE link. WAN 2 PoE link will enter the loop
of detection, power-on and power-off when the power from WAN 1 PoE Link is active.
PoE link will be power off when the power is “not” needed by load and then being going to
perform detection process that is the protection feature being described in
IEEE802.3af/at. The MPS load is a slight load, for example 50mA load for Befact PD
modules.
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