Open Vehicle Monitor System (OVMS) - Technical Discussion

[markwj]

Sorry for the late reply; with COVID-19 raging here, I haven't been able to be around TMC much lately.

The "Denied Registration" message means the cellular network denied registration to the SIM card. This normally happens when the SIM tries to connect to the network before the SIM has been provisioned. The problem is that if this happens too many times (ie; SIM repeatedly tries to connect and cellular network repeatedly denies registration), according to the GSM standard the modem must block the SIM registration for some time to stop repeated registration attempts. In my experience, the block normally clears after 24 hours or so.

There is a low level AT commands to view the block, and clear it, in the SIMCOM modem.

AT+CRSM=214,28539,0,0,12,"FFFFFFFFFFFFFFFFFFFFFFFF"

There must be exactly 24 "F" in that. After issuing the AT command, power off the modem, and power back on. Leave the device powered on for at least 7 minutes.

 

[miimura]

Sorry for the late reply; with COVID-19 raging here, I haven't been able to be around TMC much lately.

The "Denied Registration" message means the cellular network denied registration to the SIM card. This normally happens when the SIM tries to connect to the network before the SIM has been provisioned. The problem is that if this happens too many times (ie; SIM repeatedly tries to connect and cellular network repeatedly denies registration), according to the GSM standard the modem must block the SIM registration for some time to stop repeated registration attempts. In my experience, the block normally clears after 24 hours or so.

There is a low level AT commands to view the block, and clear it, in the SIMCOM modem.

There must be exactly 24 "F" in that. After issuing the AT command, power off the modem, and power back on. Leave the device powered on for at least 7 minutes.

Mark, thank you. I will try that even though it has been on and powered for a couple days already with no change.

 

[da2ny]

Per Hologram: " Monitoring - There is a currently a backlog of operations delaying SIM operations on some carriers. Backlog is processing and some customers may experience delays. Cellular network and other API services are unaffected. "
Mar 23, 15:05 UTC

 

[miimura]

I tried the AT command given above, but the "Denied Registration" status remains. Since I have not successfully used this SIM before, I will try it in another device like an iPad and make sure it works there before putting it back in the OVMS.

 

[miimura]

I took out the SIM from the OVMS modem and tried it in an iPad with cellular. It worked completely as expected in the iPad with WiFi off and speed test tracing through the T-Mobile network. I re-issued the command given above with all the F's then unplugged the OVMS module and re-installed the SIM card. Upon powerup, the status returned to "DeniedRegistration". I turned on Debug logging and stopped and started the modem from the Status page and added that log output to my support ticket at Openvehicles.

 

[miimura]

Well, it looks like it worked itself out, possibly after getting out of my garage where the signal is weak.
It's not clear to me where WCDMA lies on the 3G->4G capability and retirement continuum (spectrum is probably not a good word choice here).

 

[miimura]

Sigh... It's stuck on "DeniedRegistration" again after sitting in my garage overnight with low cellular signal. I have powered down the modem twice and it is not reconnecting, even when parked in the same outdoor location that had success yesterday.

 

[CSPHD]

I updated the firmware, installed the new modem, then tried with my existing US Mobile SIM. It was denied so I contacted their support and they said the "device" was not supported.

I obtained a Hologram SIM and it immediately connected to ATT - Hologram and then said RegistrationDenied. After eliminating signal quality issues I turned off the OVMS for 3 days to allow any cached registrations to expire (thanks @markwj for confirming that is a thing). Next, I put the OVMS on my bench and tried again but still got RegistrationDenied on ATT - Hologram. The Hologram dashboard showed I was getting a connection but no data transfer (note - Hologram is WAAAAY BETTER for iot than any other carrier I've used).

Next, I tried the Hologram SIM in a phone and it worked, but, crucially connected to T-Mobile - Hologram, not ATT. Knowing the SIM was registered and could work, I tried the OVMS again and as the modem was starting up I sent the following AT command via the ssh console

cell cmd AT+COPS=0,2,0,7

The cellular command is "operator selection" with the parameters "automatic", "numeric format", "operator=0", "access technology=EUTRAN".

At this point the modem connected to T-Mobile instead of ATT and everything has worked since then.

I cannot claim this "fixed" my issue, since I didn't try to break it and fix it again to be sure I'd found the problem. But after rebooting a few times on my bench OVMS still connected to T-Mobile - Hologram and worked. I've since reinstalled OVMS in my car and it is working.

 

[CSPHD]

I cannot claim this "fixed" my issue, since I didn't try to break it and fix it again to be sure I'd found the problem.

Replying to myself - This does not resolve the problem. After about 24 hours OVMS selected ATT-Hologram again and received RegistrationDenied. So, I still don't understand why the SIM is denied on ATT but works on T-Mobile.

 

[ShawnA]

Hi @miimura ,

If you continuously have a weak signal in your garage
you may want to try one of these "signal boosters."
I have my Roadster in a metal pole barn and I had trouble
getting a good signal through the metal roof.

https://smile.amazon.com/Booster-Cellular-Repeater-Amplifier-Antennas/dp/B09D74HS81/ref=sr_1_9?crid=4Q64QK2X9FDA&keywords=GSM+850+Mhz+phone+booster&qid=1649621937&sprefix=gsm+850+mhz+phone+booster%2Caps%2C186&sr=8-9

When I bought mine in 2018 the price was $120.
Since converting to the 4G modem it connects much faster.
The GSM signal strength shown on the app is -51 dBm to -53 dBm.

It may be worth a try...

Shawn

 

[CSPHD]

After a bit more digging, it appears the reason that OVMS does not work when it is in my garage is because the network it has chosen is not a viable option. I've drawn my conclusion from the following line of debug output:

D (99999999) cellular: mux-rx-line #4: +COPS: (3,"313 100","313 100","313100",7),(2,"AT&T","AT&T","310410",7),(1,"T-Mobile","T-Mobile","310260",0),(3,"Southern Linc","SLINC","312720",7),(3,"Verizon","Verizon","311480",7),(1,"AT&T","AT&T","310410",2),(1,"Sprint","Sprint","310120",7),(1,"312 530","312 530","312530",7),(1,"311 882","311 882","311882",7),(1,"311 490","311 490","311490",7),(1,"T-Mobile","T-Mobile","310260",7),,(0,1,2,3,4,5),(0,1,2)

It appears that in my garage EUTRAN is not viable and the selected network is EUTRAN. So, the problem is signal quality.

 

[slcasner]

I have been using the Hologram SIM that came with the OVMS long ago. When I upgraded to the 4G modem my OVMS came up and registered just fine. But then I installed a 4G modem for @Timothy who is also using the Hologram SIM and his gets the DeniedRegistration error. I posted about this to the ovmsdev list but received no response. This coming Friday I expect to get Timothy's OVMS so I can try some experiments of swapping modems or SIM cards or to see if operation in a different region makes a difference.

Following up on my earlier note. I did receive Timothy's OVMS and modem. When I tested them at my home (Sunnyvale) about two weeks or so after the installation at his home (Santa Barbara), the RegistrationDenied problem did not occur. This might be explained by a different location (so different Hologram-carrier association), different signal quality, or elapsed time. I sent the OVMS back to Timothy, he installed it back into his car, and it is working correctly there.

 

[drewski]

I've had a Google Fi data-only SIM card working in my OVMS since I installed it a few years ago. I just got a new 4G modem yesterday (Medlock has them in stock) but I haven't installed it yet. My APN is set to "h2g2"

i should try switching back to the 3G modem and see what happens with the G Fi SIM.

I'm currently back to the Hologram SIM - came with the 3G modem and not sure if it's 4G since it's connecting WCDMA in the 4G modem.

 

[ShawnA]

Hi @drewski ,

Both of my 4G modems with the Hologram SIM are showing Mode: WCDMA,Online.
I think it is OK.



My phone app connects very quickly with the new 4G modem!!!

Shawn

 

[MCroadster]

i should try switching back to the 3G modem and see what happens with the G Fi SIM.

I'm currently back to the Hologram SIM - came with the 3G modem and not sure if it's 4G since it's connecting WCDMA in the 4G modem.

I have been running my OVMS on Google Fi for the last few years. I believe that it is still running on the T-Mobile 3G system, and connects without an issue these days.

 

[MCroadster]

Is there a known way to activate the trunk lock through OVMS?

 

[markwj]

Is there a known way to activate the trunk lock through OVMS?

Not that I know of.

In general, OVMS has the capability to do what can be done from the VDS. I don't think the VDS can open the trunk.

 

[drewski]

I have been running my OVMS on Google Fi for the last few years. I believe that it is still running on the T-Mobile 3G system, and connects without an issue these days.

How do you have the settings? APN = 'h2g2' with no username / password? or something else.

 

[MCroadster]

How do you have the settings? APN = 'h2g2' with no username / password? or something else.

I believe this is the case. I'll double check.

 

[MCroadster]

I believe this is the case. I'll double check.

Was able to double check the settings and yes, that's exactly how I have it on the T-Mobile network