[Asterisk-Users] # IP601's with POE per Catalyst 3560G-48PS

[Jay Wilton]

Hello people,

I am having difficulties figuring out the POE power draw in
watts from a Polycom IP601.  I want to know how many
IP601's can be powered from the Cisco Catalyst 3560G-48PS.

The IP601 wallwart has: Input 120VAC 60hz 19W, Output 24VDC
500mA.  I assume the output is appropriate value to figure
out how many phones can be powered.

The Cisco 3560 datasheet says "the 48-port PoE
configurations can deliver the necessary power to support
24
ports at 15.4W, 48 ports at 7.7W, or any combination in
between"  ...370 Watts POE max output.

>From a UPS planning site:
Volts * Amperes = VA
VA * .8 = Watts

To convert small units into large units you divide.
Amperes = 1000/500mA = .5A

VA = 24V * .5A = 12VA
Watts = 12VA * .8 = 9.6 Watts

370 Watts maximum output / 9.6 Watts/phone = 38 phones
Does this logic hold water or change with line loss?

Thank you,
JJW

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