Connecting to Verizon

The Hologram dashboard should say “Verizon” in some way if it connected to that network.  The Hologram SIMs do work on Verizon, but they nearly always connect to AT&T in my experience.  There was a thread just a bit ago about setting the carrier profiles for the LTE-M XBee3’s , and for the time being we’ve decided that the default of “0/Automatic” isn’t stable on Hologram and we will specifically select AT&T unless it’s known to not be present at the site.

Changing the setting in profile to 3/Verizon should work, but I’ve found you might need to set it and reset or power cycle a few times before the setting “takes.”  You may also need to clear your “forbidden” list:  https://support.hologram.io/hc/en-us/articles/360035697373-How-do-I-clear-the-FPLMN-list-.  From recent conversations with Hologram tech support they say the u-blox SARA R410M is pretty quick to decide that it’s failed to connected to a network/operator and should mark that network as forbidden.

Do you have a carrier board that you can use to connect the XBee3 to the computer?  If so, then the easiest way is to use that.

Open XCTU and find the XBee3.  To type direct AT commands to the u-blox you need to be in bypass – get there by scroll down in XCTU to the “Serial Interfacing” section and change API Enable to “Bypass Mode [5].”  Click the pencil to write.  XCTU is smart enough to reset the Bee when you change the mode.  After changing that, open the terminal tab in XCTU (icon in the top right that looks like a screen with a command prompt on it).  Hit the “open” icon.  Then in the console log section you can type away.  If you don’t get an ok back after hitting enter, verify that you’re in bypass mode.  Try just “AT” several times to make sure you’re talking.  There’s no Digi commands for the forbidden list, so bypass is the only way to do it.

The StreamDebugger can work, but it’s finickey.  Usually if there’s some reason I want to talk to the XBee directly and I don’t have the carrier board with me, I write the a simple program that wakes the Bee and then sends Serial1.print("AT blah.."); and prints back Serial.print(Serial1.readString()); for everything I want to say and run that on the Mayfly.  Doing it that way usually works better for me.

If you want to use the Digi AT commands to talk to your Bee, you definitely want to change the “Guard Time” setting either with XCTU or using the Mayfly to send it “ATGT6D3” to increase that guard time back up to the default of 1 second.  To enter command mode you wait the guard time, type in three +++’s (NO ENTER!) and wait the guard time again and should get an OK.  Default is 1s wait on each side.  When TinyGSM talks to the bee, the first thing it does is cut that down to 100ms.  I can’t ever manage to type the +’s in fast enough to get into command mode unless I bump the time up again.  Once you’re in command mode you have 10s from the last successful command before it will automatically fall out of command mode and you’ll need to use the +’s again.  The “ATCN” will also immediately exit command mode.

If you’re having trouble, you can try going into bypass and checking the operator profile directly on the u-blox:  send AT+UMNOPROF?  It should reply 3 (matching up with the CP value).  If for some weird reason it doesn’t, you can change it by first disconnecting from the network, changing the profile, and then restarting:  AT+CFUN=0 (OK) AT+UMNOPROF=3 (OK) AT+CFUN=1,1 (OK, then a delay and possibly a junk character or two on restart).  The setting should hold when you go back into Transparent (and the Digi software will register the change).

Shannon and I were just talking about this – the Hologram SIM’s just really prefer AT&T.  Verizon gets written the the FPLMN list really fast.  It appears there as 311480.

😛  In double checking what the number would be for Verizon when it appears on the FPLMN, the very first google hit I got was an issue with someone else trying to force a Hologram SIM to use Verizon:  https://github.com/botletics/SIM7000-LTE-Shield/issues/163  Per that thread from just a few days ago, others suspect that Verizon has just very recently clamped down again booting out most Hologram users.

Are you totally sure you can’t just use the weak AT&T signal?  What about T-Mobile?  (As a T-Mobile subscriber, I’m dubious that there’s anywhere that T-Mobile exits and not AT&T.)  You might be able to hop to T-Mobile by using bypass and setting the UMNOPROF to 5.  I haven’t ever tried it and you might be denied by the network, but here’s a chunk of code you can add to your setup that might work:

Huh. I don’t have any *good* suggestions, but he’s a hodgepodge of things to check :

You have to use bypass or USB direct to be able to use those commands, transparent/command mode won’t work. Can you get normal responses to other commands? (ie AT – OK; ATI – modem info)  Do you have your SIM card installed? The file being cleared is on the SIM card, so it has to be installed. Do you have CFUN set to something other than 0=minimum functionality? At minimum functionality it may not be able to communicate properly with the SIM. Did you try USB direct? With the TH board you can use the side micro USB port for that – keep the USB-c plugged in for power, flip the dip switches by the micro USB both toward the plug, and then use xctu to set device options bit 2 (check the help it might be bit 4 for software usb direct enable) and enable USB direct communication on pin 7 (dio1?).

Let us know how the Verizon SIMs work for you!