Powering Meraki Outdoor MR66 Wi-Fi APs using WS-12-250-DC
Posted: Sun Sep 06, 2015 10:33 am
FYI Netonix WS-12-250-DC successfully powering 3 x Meraki MR66 APs. 
However read below as I had some problems (my own doing) - so may help others when powering Gigabit 802.3af/at devices.
Initially I had the Meraki's plugged into Ports 7,8,9 and the PoE on the Netonix set to 48V (not 48VH) and I observed that the Meraki's were only using one of their 2 radios, so either 2.4 or 5 GHz. The LAN link was gigabit.
Thought this was odd, so I did some research and found out that the Meraki's needed 48V DC 802.3af PoE.
If you look up 802.3af PoE on a gigabit LAN, you will find out that this is PoE using all 4 pairs.
48V on the Netonix is just 2 pairs.
48VH is 4 pairs.
Also, as the Meraki MR66 APs are gigabit, not matter which pairs are used, PoE is going to be run on the data lines as Gigabit needs all 4 pairs.
I guess the MR66's used just 1 radio as they didn't have the full available power available?, but it was interesting that they could work with just 2 pairs of 48V.
Perhaps some backward compatibility with 100 Mb PoE injectors?
There was no obvious warning in the Meraki dashboard with the MR66 - however I do know that some of the later Meraki APs do report power issues in the dashboard.
So I switched the Meraki's into ports 1-3, enabled 48VH (which resembles 802.11af/at) which is what the Meraki's need.
Boom. Everything working as expected.
So just make sure that if you are powering a 802.11af/at Gigabit PoE device, that it will probably need the 48VH option even if it won't use all those Watts.
The MR66's are certainly using no more than 10W so it's not like an Airfibre 5/24 which actually needs the POE on each pair for the power needed.
With the WS-12-250-DC you can only use ports 1-4 with 48VH so you will need to think about another switch if you don't have enough ports.
All okay in our case however.
(We have some CRC errors on those lines. Nothing really big but something of interest.)
However read below as I had some problems (my own doing) - so may help others when powering Gigabit 802.3af/at devices.
- meraki netonix.png (126.69 KiB) Viewed 5400 times
Initially I had the Meraki's plugged into Ports 7,8,9 and the PoE on the Netonix set to 48V (not 48VH) and I observed that the Meraki's were only using one of their 2 radios, so either 2.4 or 5 GHz. The LAN link was gigabit.
Thought this was odd, so I did some research and found out that the Meraki's needed 48V DC 802.3af PoE.
If you look up 802.3af PoE on a gigabit LAN, you will find out that this is PoE using all 4 pairs.
48V on the Netonix is just 2 pairs.
48VH is 4 pairs.
Also, as the Meraki MR66 APs are gigabit, not matter which pairs are used, PoE is going to be run on the data lines as Gigabit needs all 4 pairs.
I guess the MR66's used just 1 radio as they didn't have the full available power available?, but it was interesting that they could work with just 2 pairs of 48V.
Perhaps some backward compatibility with 100 Mb PoE injectors?
There was no obvious warning in the Meraki dashboard with the MR66 - however I do know that some of the later Meraki APs do report power issues in the dashboard.
So I switched the Meraki's into ports 1-3, enabled 48VH (which resembles 802.11af/at) which is what the Meraki's need.
Boom. Everything working as expected.
So just make sure that if you are powering a 802.11af/at Gigabit PoE device, that it will probably need the 48VH option even if it won't use all those Watts.
The MR66's are certainly using no more than 10W so it's not like an Airfibre 5/24 which actually needs the POE on each pair for the power needed.
With the WS-12-250-DC you can only use ports 1-4 with 48VH so you will need to think about another switch if you don't have enough ports.
All okay in our case however.
(We have some CRC errors on those lines. Nothing really big but something of interest.)