Help with SIM7000E PPP Setup on Raspberry Pi Zero W

ChirpStack Gateway OS
1

Hello,

I’m currently trying to set up a SIM7000E cellular modem with a Raspberry Pi Zero W running ChirpStack 4.7.0 base. I am aiming to establish a PPP connection over the SIM7000E by waveshare. However, I’ve encountered some issues and could use your assistance.

Hardware Setup:

  • Raspberry Pi Zero W with ChirpStack installed.
  • SIM7000E HAT connected via UART (specifically, /dev/ttyAMA0).
  • PPP connection established using pppd and the necessary chat script for the SIM7000E.

Packages Installed:

  • ppp
  • comgt
  • minicom
  • chat

Problem:

I can communicate with the SIM7000E using minicom and send AT commands successfully (e.g., AT, AT+CSQ, etc.), but when trying to initiate a PPP connection with:

sudo pppd call sim7000

The process hangs, and I do not get a working PPP interface (ppp0). I can also see the serial port (/dev/ttyAMA0) being used but am unable to see much activity when I run:

cat /dev/ttyAMA0

Things I’ve Tried:

  • Verified the SIM7000E is correctly initialized with minicom using basic AT commands (e.g., AT, AT+CSQ).
  • Tested the chat script for sending commands like ATZ, but the script hangs at AT and doesn’t move forward.

Additional Info:

As I have already configured this setup on Raspberry Pi OS, I suspect the issue lies within the software environment on ChirpStack which appears to be more stripped down. Specifically, in the /etc/ppp directory, I see fewer files and folders, which makes me wonder if this could be a contributing factor to the problem.

Questions:

  1. Does anyone have a working chat script for SIM7000E on Raspberry Pi Zero W that I can compare against my current setup?
  2. Are there any specific PPP options or serial port configurations I may have missed for stable connectivity?
  3. Is there any advice or debugging steps that could help identify what’s causing the “Connect script failed” issue?

Thank you in advance for any guidance or suggestions you can provide!