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4G in the United States - T-mobile based doesn't seem to register

Recently bought an OVMS v3.3 w/ the 4G card on it for my Nissan Leaf.  Been slowly bringing it up, and getting it all figured out.  One of the things I wanted to do was intentionally swap the sim card over to Google Fi, since I already have data there and it's $10/GB vs. $80/GB for hologram (nothing against hologram in the least here).

So I've been trying to get the sim7600 to come up on Fi and haven't been succeeding, specifically running into (after a while) DeniedRegistration, but it does discover that it's Google Fi.  This is using APN: h2g2, as APN: h2g2-T (as checked from a google phone) didn't seem to actually connect at all.  I've tried moving it around and such and nothing really seemed to resolve this so far.

So to help, at least bound the problem some, I signed up for hologram and put that sim card back in, and more or less it came up straight away and was on AT&T's network it looks like

MODEM Status
Model: SIM7600
Network Registration: RegisteredRoaming
Provider: AT&T Hologram
Signal: -73 dBm
Mode: State: NetMode
Mux: Status up
PPP: Connected on channel: #2
GPS: Connected on channel: #1


Since I've also got a T-mobile sim I decided to toss that in that in and using APN: Fast.t-mobile.com, I'm seeing the same thing as I was seeing with Google Fi, with the only difference been a -T-Mobile carrier string vs. Google Fi.

MODEM Status
Model: SIM7600
Network Registration: DeniedRegistration
Provider: T-Mobile
Signal: -69 dBm
Mode: State: NetWait
Mux: Status up
PPP: Not running
GPS: Connected on channel: #1


This is leading me to think that T-Mobile (since Google Fi is effectively an MVNO over the top of their network) seems to be blocking the SIM7600G, and curious if anyone else is seeing this issue with another T-Mobile mvno in the 'States, or has their 4G working on T-Mobile itself.  (noting the Google Fi and T-Mobile sim cards work fine in a couple of different phones I have and pass data without issue, thus why I'm narrowing this down to seemingly the sim7600g as the likely pain point and maybe while T-Mobile might be blocking it?)

Stanton's picture
I suspect there is something

I suspect there is something with Google Fi (don't pretend to know what) that is incompatible with OVMS (server/network/whatever).

I also understand you are trying use data/service you already have, but you do realize that it would take you months (if not years) to use even 1 Gbyte of data with OVMS?

it's not Google Fi, it's T

it's not Google Fi, it's T-Mobile that's got it blocked at the tower seemingly (thus why I tried the T-Mobile sim, and it's seeing the registration fail from the modem, upstream servers for OVMS haven't even come into the picture by that point).  The problem is there's only 3 carriers in the US: AT&T, T-Mobile, and Verizon - everyone else (including Google Fi) are MVNOs that just exist over the top of one of those 3.  Verizon also tends to be "weird" and definitely not exactly open, which means there's only one working carrier.  Coverage is inconsistent across the carriers, and a whole slew of other reasons.  Having, effectively, 50% of the possible carriers unavailable is concerning.  Bonus points, my car is currently sitting on Hologram's 3G network, not 4G LTE, so coverage right where I'm at for LTE and AT&T is not great (and I'm within the greater metro area of a somewhat large city)

As for the amount of data, out of the box: yes OVMS isn't using much, so far in this period I've already used 1MB of data.  That's not a lot I'll grant but if I wanted to start having OVMS report more data more frequently to my own server pricing on hologram can get prohibitive.  Obviously the path that should work would be to switch to an AT&T based MVNO, but was hoping someone else might have contacted, likely T-Mobile, before I go trying to poke this one on my own

markwj's picture
Note that 'Registration

Note that 'Registration Denied' is a very very early error during the SIM card registration process. This is commonly caused by the SIM being inserted into OVMS and turned on (trying to register on the cellular network) before the SIM is registered and activated. The modem has a cache, and if too many registration denied responses are received from the cellular network then it caches that and won't try again for several hours (even if in the interim, the SIM is registered and activated). The APN is unrelated, as that is used much later for the data connection. There is no configuration in OVMS for this cellular registration, and it is all on the cellular side.

We have a large number of OVMS users using T-Mobile (both directly and via MVNO).

Warthog9, were you ever able

Warthog9, were you ever able to get Google Fi working?

I too have been trying to get

I too have been trying to get my OVMS connected to T-Mobile. After two very long sessions with Tech Support at T-Mobile no progress has been made. They can see my SIM7600G modem and read the IMEI so there is a connection. The most recent conclusion form their end is that the MODEM is not accepting the T-Mobile network much in the same way as a cell phone can be locked so as to work on a specific network.

When I monitor the operation of the modem it very briefly, perhaps a second, shows that is is registered to T-Mobile. Looks like:

Model: SIM7600

Network Registration: RegisteredHome

Provider: T-Mobile

Signal; -81 dBm

Mode: LTE, Online

State: NetStart

Mux: Status up

PPP: Not running

GPS: Not running


Following this very brief state the status change to Registration: Unknown and Provider blank.

APN for T-Mobile?

Still trying to get my OVMS to work with T-Mobile SIM (purchased direct from T-Mobile).  Can anyone tell me the correct APN? Is the SIM pin number important?

Any luck?

Did you have any luck getting t-mobile to work? I am in the same boat.

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