I’ve deployed my Pi Zero W with the IoT HAT out in the field and it just barely works. It has excellent LTE signal. When it’s connected, AT commands show that it has -61 dBm RSSI and 4.19 dB SINR on LTE BAND 12, CAT-M1. However, I can’t maintain a PPP connection. Once it connects, it only lasts for a few minutes before getting kicked off and having to start over again. I have a PPP connection for about 2 minutes out of every 10.
This what my ppp peer file looks like:
# /etc/ppp/peers/provider /dev/ttyUSB3 460800 # The chat script, customize your APN in this file connect 'chat -s -v -f /etc/chatscripts/chat-connect -T h2g2' # The close script disconnect 'chat -s -v -f /etc/chatscripts/chat-disconnect' # Hide password in debug messages hide-password # The phone is not required to authenticate noauth persist # Debug info from pppd debug # If you want to use the HSDPA link as your gateway defaultroute # pppd must not propose any IP address to the peer noipdefault # No ppp compression novj novjccomp noccp ipcp-accept-local ipcp-accept-remote local # For sanity, keep a lock on the serial line lock modem dump updetach # Hardware flow control nocrtscts remotename 3gppp ipparam 3gppp ipcp-max-failure 30
Sometimes this is what the ppp log shows when it loses its connection:
pppd: rcvd [LCP TermReq id=0x2c] pppd: LCP terminated by peer pppd: Connect time 2.8 minutes. pppd: Sent 1425461 bytes, received 1031159 bytes. pppd: Script /etc/ppp/ip-down started (pid 1272) pppd: sent [LCP TermAck id=0x2c] pppd: Modem hangup pppd: Connection terminated. pppd: Script /etc/ppp/ip-down finished (pid 1272), status = 0x0
Other times, the
ping test in the script that runs ppp fails, so it runs
pon. I even changed the
ping command to
-c 10 instead of
-c 1 to make sure it’s REALLY disconnected instead of just 1 failed ping, and that didn’t seem to help.
I’d be happy to provide more context if you have any questions. Any help is greatly appreciated.