Hello,
I recently inherited administering a Cambium PMP setup and I am trying to understand the purpose and utilization of the CMM5 we have currently. We do not have much documentation on the setup, so I am trying to figure this out now.
I know that the CMM5 will pass PoE to our 2 450m APs. Also, I know there is some type of GPS functionality involving the CMM5. I also believe from the documentation from Cambium I have read that there is a timing functionality to this setup to help the connection from APs to SMs.
The 450m’s we have show that they are receiving 100% Cambium Sync from the Power Port, but I am unsure if this actually does anything currently? Please see screenshot below:
From what I have read as well, should the AP be sending out GPS information or data of some sort to the SMs? I have the configuration for the Sync settings on one of our 450m’s below. My current guess/theory is the Sync Input should be set to “Generate Sync” to send out information to the SMs? This is where I currently seem to be stuck at looking into this.
My main goal from this is to use all the functionality we have within our setup currently. Is there some way to get any information the CMM5/GPS is used for to load into our cnMaestro instance? If our CMM5 setup is not properly configured, what added features/benefits would we see to our radios and setup?
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So the CMM5 is used for both PoE and GPS sync injection to connected PMP450 AP’s. The CMM5 is kind of a dumb device, so there’s not a whole lot of need to do anything with it. The GPS signal is used for consistency amongst sites and keeps the AP’s all running at the same pulse. In the first screen shot you’ve shown that “Cambium Sync” is being delivered, so that’s good! On the second screenshot, that shows the correct configuration for sync. I would not change the sync input to generate, as that would break the timing between the other AP’s and other sites.
Please take a look at this group of articles regarding the CMM5 and sync in general to get a better understanding of how this all works:
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Thank you for the explanation!
So the GPS function is used for timing, but is there any GPS data that we can leverage from these devices into our cnMaestro instance? Ex. currently I have manually plugged in the estimated coordinates for our devices into cnMaestro so we can utilize the map tool.
Also, is there any sync/data from the GPS/CMM5 that is getting sent to the 450b’s? If so, what would that be and where would I find it?
As to your first question, no. The CMM5 is only providing a sync signal via ethernet and not the actual GPS data to the AP. I believe if you’re using a cnPulse GPS unit connected to the AP’s AUX, then it would pass on that GPS data to the AP, and you’d see the details under “GPS Status”… that being said, even when using cnPulse, and having the GPS data on the AP, I do not think that information is conveyed to cnMaestro.
As to your second question, no, there is no GPS data coming from the AP and being delivered to the SM’s.
The access point is in generally in charge of the timing of the sector. It defines when it can transmit and when each of the subscriber modules can transmit. This is true regardless of whether the AP is using GPS sync. SMs don’t need to receive GPS sync data specifically, because they just follow the APs timing.
GPS sync is important when you have more than one AP, to ensure that the APs don’t interfere with each other.
