How do I activate my T-Mobile SIM cards using a Netgear LB1120 4G LTE Modem?

  • 14 June 2018
  • 4 replies

I bought three T-Mobile SIM Starter Kits to use in three Netgear LB1120 4G LTE modems.


The instructions gave me two ways to activate:

1. visit

2. call 1-877-778-2019 from your device


I can't do 2 because my device does not have the capability to dial out.

These Netgear LB1120s do not have dial-out capability.


So I tried

I got routed to

Now I'm lost.

It seems the web sites are always updating beyond what is printed on the instruction sheets.


What's the best way to get these SIM cards activated on my three Netgear modems?

Also, I will need to be assigned three new phone numbers to manage my T-Mobile Refill cards.

The dial-in method works great with T-Mobile Refill cards provided I have phone numbers.


Or could I grab an old unlocked GSM phone to do the activation with the T-Mobile app and then move the SIM cards over to the Netgear LB1120 cell modems?

Would that work? Be easier to manage?

4 replies

Userlevel 4


So are you trying to activate the SIM cards only, and already have existing lines? Or are you attempting to establish the lines as well?


Userlevel 3

Hey, @magneto4794170​!

Did you get your SIMs activated already? If not, please get back to us with answers to Lauren's questions so we can better understand the situation.

Userlevel 3

Hi hi! Hoping that we haven't heard back from you because you're already up and running -- but if not, we'd love to snag some more details so that we can point you in the right direction! 😊 Thanks!

So,… I’m having a similar issue with my Netgear LB1120 Modem. I have been with Sprint for 17 years and I learned that the modem does not accept the Sprint Sim card so I went to Tmobile  and had them issue a new Tmobile Sim card for my cell phone. The modem is supposed to pic up your provider network when you install the sim card however, I can’t seem to get it to recognize my Tmobile card?


Any ideas?