Now that I have some more experience with using routerboard LTE hardware on the AT&T network I figured I would share my experience.
I have an unlimited plan, it’s one of the older plans that they don’t sell anymore. I do have a grandfathered “ZTE home phone with internet” on the account. I have been unable to use the sim from the ZTE hotspot because AT&T considers the device a phone because it can make phone calls. When I put the sim in any non-phone device, including tablets, it doesn’t work.
All that considered I have had great success with a WapR with a Sierra wireless lte card for quite a few months. That sim is under contract and came out of a tablet. No special configuration was needed on AT&T’s side, I just put in the sim, configured the router and was online.
All was not well when I tried to get another sim for a new LHG-LTE-KIT-US. AT&T recognized the device IMEI number and said I had to go to a store to get the SIM. The store said the device didn’t work on AT&T’s network and wouldn’t get me a sim. I ended up ordering a sim for a old tablet that I had through the bring your own device program. I took a look at my account when I got the sim today and it was provisioned for the tablets IMEI. The sim worked in the tablet with no activation so I stuck it in the LHG-LTE and the LTE interface came right up and works flawlessly.
Lesson of the story? Order a sim for a tablet and stick it in the routerboard.