Timing Inquiry

Products PMP
1

Suppose I have a cluster-style mount, and on this mount I have:

(2) 5.7 GHz 20 Mbps Advantage APs

(1) 5.2 GHz 20 Mbps Backbaul Module

If I configure AP-1 to Generate Sync…

If I configure AP-2 to derive sync from its RJ-11 timing port…

If I connect a straight-through RJ-11 to RJ-11 cable between AP-1 and AP-2…

If I configure the 5.2 GHz Backhaul module to generate sync…

I should not have any issues, correct?

I am trying to avoid using a CMM, for cost purposes and in this particular application, there is no “nice, neat” location to install one.

Thanks,

Matt

2

Since the site backhaul is 5.2GHz you shouldn’t see any issues.

Just make sure like you planned, that the AP’s are synced together.

This does not resolve this cluster being out of sync with the rest of the network though, but if it is a stand alone system far enough away it won’t matter.


If you have sync at the other end of the backhaul, you could draw sync across the backhaul and pass it into the AP’s…

3

Thanks for the reply.

This is for a small living community with about eleven (11) buildings, all very close together. The complex itself is in the middle of no man’s land.

Thanks,

Matt

4

+1 seems fine to me. As long as there is no other 5.7 Canopy nearby and your 5.2 BH is isolated there shouldn’t be any problems

5

There are some other cost effective solutions for timing other than a CMM. You could look at a Syncpipe or LMG has a CTM Express8 which is around 1/3 the cost of a CMM. If you can fit one into your budget, a external timing solution IMO is still be best route.

6

When creating a sync cable, do all pins get terminated in the RJ-11, or just the ones used for timing?

Something makes me recall an issue occurring when all pins were terminated…a module thought that it had a “default plug” terminated to the RJ-11 port?

Thanks,

Matt

7

Yep. If you terminate straight through you will make it think it has a default plug in it.

Just the sync pin and ground, which is pin 1 and pin 6.

8

Thanks.

9

I have an offshoot question sorry to distract but it seems you guys have this wrapped up…does anyone know how long you can make a sync cable before the sync signal attenuates?

10

I have heard something like 200 feet or so, but I don’t know the exact number. I never have had the need to find out.