Phoenix Contact Power Supply & UPS Connection

[SG-1]

I have a Phoenix Ultra Cap 20kj module & a Phoenix Quint UPS. Both modules has a terminal marked with a square wave symbol.  Both modules have two other terminals marked + & - for the DC input or output.

What is the third terminal marked with the square wave for ?

https://www.phoenixcontact.com/online/portal/us?uri=pxc-oc-itemdetail:pid=2320380&library=usen&tab=1

Click on Technical then block diagram.

[Bratster]

According to the manual on the page you linked it appears that is a communication wire between the UPS module and the battery module.

That is my conclusion based on the system apparently having a smart battery and the only wiring photo shown is just power, ground and the square wave wire connecting the UPS module to the battery module.

But the manual doesn't outright say that, or even show any real wiring diagrams for that matter.

So I could be totally wrong haha.

Sent from my Pixel 2 XL using Tapatalk

[SG-1]

Poor documentation for sure. Could it allow the power supply to operate in flyback mode ? 

Is there any particular Greek letter that is now used for flyback ?