PPP Problems When Connecting to a Cell Network with Raspberry Pi

Connectivity LTE Cat-M1 & NB-IoT
1

I am trying to use a Nova R410M connected to a Raspberry Pi Zero W running Raspbian Buster to upload a single file via FTP and I am having a problem connecting to the cell network. When I run sudo hologram network connect -v, everything seems fine and it says that “PPP session started” but when I try to ping 8.8.8.8 (or do anything involving the internet), I get “Network is unreachable” or similar. When I run ifconfig, no ppp device is listed (only lo, wlan0, and wwan0 are listed). The weird thing is that every once in a while after I run sudo hologram network connect and then ifconfig, I do see a ppp device listed but I still can’t connect to the network and when I rerun ifconfig, the ppp0 device has disappeared. sudo hologram network disconnect seems to behave as expected. My signal strength seems fine (26,99) and my operator is listed as Verizon Wireless Hologram.

Does anyone have any idea what is going on or how to fix this?

2

Hi, can you try doing:
hologram modem reset
Then wait 20 seconds or so and then try to run connect again?

If still doesn’t work, can you run connect with -vv and post the logs here?
Thanks

3

hologram modem reset doesn’t fix the problem.

This is the output from connect -vv:

DEBUG: checking for vid_pid: (‘12d1’, ‘1506’)
DEBUG: checking for vid_pid: (‘12d1’, ‘1001’)
DEBUG: checking for vid_pid: (‘05c6’, ‘90b2’)
INFO: Detected modem NovaM
DEBUG: checking port ttyUSB0
DEBUG: checking port ttyUSB1
DEBUG: [AT]
DEBUG: {AT}
DEBUG: {OK}
INFO: found working port at ttyUSB1
INFO: chatscript file: /usr/local/lib/python2.7/dist-packages/Hologram/Network/Modem/chatscripts/default-script
DEBUG: [ATE0]
DEBUG: {ATE0}
DEBUG: {OK}
DEBUG: [AT+CMEE=2]
DEBUG: {}
DEBUG: {OK}
DEBUG: [AT+CPIN?]
DEBUG: {}
DEBUG: {+CPIN: READY}
DEBUG: {}
DEBUG: {OK}
DEBUG: [AT+CPMS=“ME”,“ME”,“ME”]
DEBUG: {}
DEBUG: {+CPMS: 0,23,0,23,0,23}
DEBUG: {}
DEBUG: {OK}
DEBUG: [AT+CMGF=0]
DEBUG: {}
DEBUG: {OK}
DEBUG: [AT+CNMI=2,1]
DEBUG: {}
DEBUG: {OK}
DEBUG: [AT+CEREG=2]
DEBUG: {}
DEBUG: {OK}
INFO: Instantiated a NovaM interface with device name of /dev/ttyUSB1
DEBUG: [AT+CGMM]
DEBUG: {}
DEBUG: {SARA-R410M-02B}
DEBUG: {}
DEBUG: {OK}
INFO: Connecting to cell network with timeout of 200 seconds
INFO: Checking for existing PPP sessions
INFO: Starting pppd
INFO: Successfully connected to cell network
INFO: Adding routes to Hologram cloud
INFO: Adding system-wide default route to cellular interface
PPP session started

4

I solved my problem, sort of. I switched over to a Raspberry Pi 3 B and an official Raspberry Pi 2.5A power supply and everything works. I was running the modem through a USB hub connected to a Raspberry Pi Zero W and I think the problem was that the USB hub or its cable wasn’t allowing enough current to get to the modem. I tried several different power sources and several ways of powering the Pi and the USB hub and was only able to get the modem to fully work intermittently. Perhaps a better quality, powered USB hub would work with the Pi Zero but the cost of all of that comes close to the cost of a Pi 3 B so I’m going with that for now.

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