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igpetkov
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Joined: Thu Oct 09, 2014 10:27 pm

Pair CAP AC

Mon Feb 04, 2019 2:56 pm

Hello everyone,
I need to add more AP to my existing wireless network, but do not option for more cables.
I think to change my old AP with RBcAPGi-5acD2nD and connect to two RBcAPGi-5acD2nD to one cable.
The all new pieces RBcAPGi-5acD2nD will be 20 (10 cablesx2RBcAPGi-5acD2nD). I plan to connect them to CRS328-24P-4S+RM.
In specification of CAP AC - Max power consumption without attachments 13 W.
If i connect second AP to PoE Out on first is that consumption stay 13W?
Can I connect that pair (two RBcAPGi-5acD2nD) to one port of CRS328-24P-4S+RM?
How many pairs can I connect to one CRS328-24P-4S+RM?
Can I powered 20 pieces with one CRS328-24P-4S+RM or have to place two switches?

Thank You
 
mkx
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Re: Pair CAP AC

Mon Feb 04, 2019 4:03 pm

Specs of CRS328-24P-4S+RM state that max PoE out per port is 1000mA and grand total is 20A. PoE out voltage is selectable. As cAP ac can take up to 57V in, it is recommended to set 53V as PoE out from CRS (propaganda leaflet claims that either 26V (passive PoE) or 53V (802.3af/at standard) can be selected per port.

cAP ac, per specs, consumes 13W. At 50V (let's give some room for voltage drop on ethernet cables) this translates to 260mA. PoE out on cAPac is limited to 400mA, so this is sufficient for powering the second unit. Both units together should consume around 520mA, which is well below the CRS port limit.

Total power consumption of 20 cAPs would be around 5.2A, which is well below the grand total limit (which is 20A).

So yes, it should be possible to do what you described as target topology.
BR,
Metod
 
igpetkov
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Joined: Thu Oct 09, 2014 10:27 pm

Re: Pair CAP AC

Mon Feb 04, 2019 4:39 pm

Thank You, mkx!
Even the second CAP to use low voltage, because PoE out on CAP Ac is Passive PoE the current will be 13W/26V=0.5A. And then 0.5+0.260=0.760 per port on the switch. We have 10 pairs and total consumption will be 7.60A. Haw you say: "well below the grand total limit (which is 20A)."
With one Switch I can powered 10 pairs (20 AP)

Is that right?

Thank You again about your help
 
mkx
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Re: Pair CAP AC

Mon Feb 04, 2019 8:46 pm

Nope, cAP will just pass-through power supply. But anyway, from power point of view you'll be fine.
BR,
Metod

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