Using the TMobile ISP Box sim in a Netgear LB1120

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I have the unlimited TMobile ISP internet modem, and it works ok, but it has limitations that I can solve by using a different modem.  The TMobile ISP box does NOT have a bridge mode and it does NOT have external ports for external antennas.  For those of us in rural areas this means we get maybe 1 bar of service.  The NO bridge mode means I either intend to let the TMobile modem be a router as well as a modem, and I don’t like this idea for several reasons: 1) The firewall sucks.  2) no masquerade 3) No detail configurable firewall with subnets, 4) No embedded GPS for location & 5) the 2.4 & 5 Mhz Wifi is not powerful enough to reach the far corners of the home and those emitters interfere with the cellular signal at 1 bar, making upload speeds suck for a Plex server.  So I prefer my Mikrotik router, and my Mikrotik AP’s stanmding alone on the network - which means I need the TMobile ISP modem to be in bridge mode, (but they don’t have a bridge mode) or I’ll encounter a double NAT issue.  There are too many ports to attempt to forward on my network and opening the DMZ is counter intuitive to the purpose of a true masquerading firewall.  So using the TMobile modem as a DHCP server/firewall is not an option I’ll consider. 

So I purchased the Netgear LB1120 modem and proceeded to transplant the sim from the TMobile modem into the Netgear 1120.  I set the APN to fbb.home and - nothing.  It will not connect to the TMobile network.  No bars.  I installed a generic TMobile sim card in the Netgear LB1120 and it comes right up - with 1-2 bars.

So how do I configure the Netgear LB1120 to use the sim card out of the TMobile ISP modem?

If I can get it to work I can install the L400 cables to the external grid antennas outdoors, pointed at the nearest cell tower, and I should get 5 bars and a truly descent internet experience.

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I talked to Tech Support last week, asking if the SIM card is locked to the RTL0102, however, they weren’t able to answer that and suggested I go ahead and try with a different modem. I’m currently running an OpenWRT platform with a EP06 modem on AT&T. The only T-Mobile band I receive at my location is band 71 (600MHz) when I take the box up on the roof or string it up 40 feet in the air on a tree. So I went ahead and purchased an EC25-AF, which covers Band 71. Long story short, it does not work with the T-Mobile Home Internet SIM. Another call into tech support today confirmed that the SIM only works in the RTL0102 it was shipped with. There are no plans to change that. The new 5G version of the modem-router likely will have no external antenna ports either. So unfortunately, T-Mobile Home Internet is not for people in rural areas, which is ironically who this service was aimed at. 

Modify the IMEI on the Quectel modem to match the RTL0102.  I’ll take the spare off your hands if you’re sitting on a surplus of modems, of course!

Did you ever solve this? 

Working great now - simple configuration error was holding me up.



Do you mind detailing the configuration error?

I just spent a few hours trying to get the sim from a Nokia 5G21 working in a Nighthawk M1, pretty much for the same reasons as you -- the 5G21 doesn’t support IP passthrough, etc. and I’d really prefer not to be doubled up on NAT, etc.

Anyway, I changed the Nighthawk IMEI to match that of the 5G21 and still could not get it working. I tried the various APNs --, b2b.static, etc. The only thing I didn’t try was an IPV6-only LTE setting.

The Nighthawk is registering signal strength, etc. but says “Mobile Broadband Disconnected”.

Considering Home Internet is a truly unlimited plan, it really should not matter what device is used. Not to mention they advertise a BYOD (Bring Your Own Device) policy anyway.

Thanks in advance for any help.

@BL76 The APN for the home internet service is:  fbb.home


You’re not going to get anywhere with that not set correctly.  APN and IMEI shoudl be all you need.

Did you get this to work?

I’ve got a WE826-T2 with an EC25-AF in it that gets -way- stronger connection signal than the trashcan (good antennas!) - BUT, even after cloning the trashcan’s IMEI and with it SHOWING THE MODEM AS CONNECTED, with fbb.home as the apn, …

...I get no IP addressing and can’t hit the internet.

I think they use some custom LAN with maybe static addressing behind the connection to the cell network?…


I picked up a data only sim card for $10 and added to my account.

I was able to activate it and get it working in my Netgear LB1120.

I only want to use this as backup connection to manage my home network in the event my primary fiber is down.

I have the LB1120 connected and receiving a public DHCP address from TMobile on a Juniper SRX firewall I have… but it appears TMobile actually NATs me again to a different public address than what was given via DHCP to my firewall. 


This is keeping me from being able to connect remotely (from trusted sources) to anything inbound… including the public interface of my SRX firewall.

Is this just a limitation of the data only sim card?

I know this is a bit old, any updates?


Did any of you try IPV6 only. Looking at what the trashcan gets it appears to only get an IPV6 ip. No V4. Although an ipleak test shows an external IP. Maybe they are using a gateway on the ISP end and routing everything over IPV6 wirelessly. My guess is you would have to set your LAN up to bridge


I reviewed a bunch of the JS happening on the web UI. There are API functions for everything you could want. I just have to figure out the details needed to send the requests. There may be hidden pages that could set things. I see port forwarding, IPV4 address, Access Polocies, QOS, Etc. 

You CANNOT use the SIM from inside the gateway.

As long as the device you are transplanting it to has the same IMEI, you absolutely can.  I use a Mikrotik RB and a Quectel LTE modem (see my posts above), which I now have working.

The TMobile ISP box does NOT have a bridge mode and it does NOT have external ports for external antennas.

TMO’s major limitation is that even if you do get a gateway device with bridge mode (or any other NAT function), TMO’s CGNAT implementation makes life difficult.  Possible solution = OpenVPN on a $2/mo VPS.

So I prefer my Mikrotik router, and my Mikrotik AP’s standing alone on the network.

I recommend you try my solution above if you like Mikrotik (I used the smallest board, but there are several other options).  Works great and the management across my network is consistent and easy if you are already familiar w/ Mikrotik.  Also, there are many other modem choices out there depending on what bands and technology (LTE / 5G) you wish to accommodate (and your budget, of course!).


Hi networkdaemon! I’m working on this exact issue for a family member. I have an external yagi antenna (roof mounted) as well as a pfsense firewall and a few piholes that i set up for them, bridge mode would be amazing.


I’m comfortable with Linux, but never played around with Mikrotik and will be spinning up on that this weekend.


Can you share any notes on your process to get this working, maybe on Reddit or in this thread? I did a little research on carrier grade NAT, sounds like a little AWS instance will do the trick nicely.