POE 802.3af standard and catalyst 3560 (8 port switch)

From: Radioactive Frog (pbhatkoti@gmail.com)
Date: Sat Sep 29 2007 - 01:20:41 ART


There are different implementation of 802.3af standards in different
vendor's switches..

I have tested that found out that cisco 3560 switch implements it using
DATA-PAIR i.e. pin 1,2 and 3, 6.

My questions are:

1. How does it actually works? supplying DC voltage and ethernet data
through the same wires?
2. Do they use some sort of DSL technology stuffs (phone and data on
different frequency?)
3. How does 3560 POE switch detects non-POE device? For example, plugging a
laptop on Cisco 3560 switch and it does't blow up?

Just curious to know.

POE pinouts from different manufacturers STANDARDSOURCELOADREMARKS Ethernet
RJ-45 connector pin number Source Voltage 1 2 3 4 5 6 7 8 Load Voltage DC
Load Connector IEEE 802.3af
using data pairs 48 V DC, protectedRX, DC+RX, DC+TX, DC-sparespareTX, DC-
sparespare(embedded)Industry Standard for embedded PoE IEEE 802.3af
using spare pairs48 V DC, protectedRXRXTXDC+DC+TXDC-DC-(embedded)Industry
Standard for embedded PoE Intel, Symbol, OrinocoUsually
12 or 24 V DCRXRXTXDC+DC+TXDC-DC-(embedded)Most Brands of PoE Cisco
(OLD old standard)48 V DCRXRXTXDC-DC-TXDC+DC+(embedded)Older Cisco polarity
is
REVERSED Cisco
(NEW old standard)48 V DCRXRXTXDC+DC+TXDC-DC-(embedded)New Cisco is IEEE
compliant D-Link (Adapter)48 V DCRXRXTXDC??DC??TXDC??DC??5VDC @ 2.5ADC
coaxial
5.5/2.5mmD-Link PoE Adapter for non-PoE products. Apple MacIntosh AirPort
PoE, Extreme48 V DCRXRXTXDC??DC??TXDC??DC??Converted to ???DC coaxial
(???)Mac Polarity Unknown HyperLinkMany DC Voltages AvailableRXRXTXDC+DC+TX
DC-DC-same as inputDC coaxial and others availableVariety of Options
Available to Fit Most Brands of PoE NYC Wireless
"Roll Your Own"12 or 24 or 48 V DCRXRXTXDC+DC+TXDC-DC-same as inputDC
coaxial
or as reqdNew York City Wireless PoE

PoE - powered devices should obey following specifications:

Frog..



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