Can my employer see my personal cell phone data on their network extender?

[STEBEE85]

If my employer has a network extender, through their internet,  can they see my personal cell phone data/call activity? Or is it private?

[lukevinyl · Accepted solution]

They definitely can't see any activity.

[lukevinyl]

And actually, they can't even see the phone numbers of the devices that are connecting on their network extender (though they can set a "whitelist" for devices allowed on the network extender if they choose to).