Avaya Power Over Ethernet Practical Manual page 25

Appendix B
The IEEE 802.3af standard defines a lower and upper guard-band around the resistive signature range.
Any PD value in the guard-band range is considered non-compliant. Additionally, PD values beneath or
above the guard-band ranges are considered invalid signatures. Both invalid and non-compliant signatures
mandate removing power almost instantly by the PSE.
Table B – Parameters for an invalid or non-compliant power signature
Parameter
Voltage Ramp-up
Input Capacitance
Lower Guard-band
Upper Guard-band
MJK
Copyright ©
IEEE 802.3af Guard-bands and beyond
Conditions
V < 10.1V
V < 10.1V
Start up and Steady State
Start up and Steady State
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Range of Values
12K Ω < or > 45K Ω
> 10 µF
12K Ω – 23.75K Ω
26.25K Ω – 45K Ω
Condition
Invalid Signature
Invalid Signature
Non-Compliant
Non-Compliant
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