pppd problem: Hangup (SIGHUP) after Protocol-Reject

Question

I'm trying to set up a connection using a Vodafone LTE sim card on a carrier board with a Qualcomm modem equipped and with Linux Yocto running. I managed to turn on the modem but I can't connect it to internet. I can paste the syslog down here:

Nov 19 17:27:27 imx6ull-microgea chat[667]: abort on (BUSY)
Nov 19 17:27:27 imx6ull-microgea chat[667]: abort on (NO CARRIER)
Nov 19 17:27:27 imx6ull-microgea chat[667]: abort on (VOICE)
Nov 19 17:27:27 imx6ull-microgea chat[667]: abort on (NO DIALTONE)
Nov 19 17:27:27 imx6ull-microgea chat[667]: abort on (NO DIAL TONE)
Nov 19 17:27:27 imx6ull-microgea chat[667]: abort on (NO ANSWER)
Nov 19 17:27:27 imx6ull-microgea chat[667]: abort on (DELAYED)
Nov 19 17:27:27 imx6ull-microgea chat[667]: report (CONNECT)
Nov 19 17:27:27 imx6ull-microgea chat[667]: timeout set to 6 seconds
Nov 19 17:27:27 imx6ull-microgea chat[667]: send (ATQ0^M)
Nov 19 17:27:27 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:27 imx6ull-microgea chat[667]: ATQ0^M^M
Nov 19 17:27:27 imx6ull-microgea chat[667]: OK
Nov 19 17:27:27 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:27 imx6ull-microgea chat[667]: send (ATZ^M)
Nov 19 17:27:28 imx6ull-microgea chat[667]: timeout set to 3 seconds
Nov 19 17:27:28 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:28 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:28 imx6ull-microgea chat[667]: ATZ^M^M
Nov 19 17:27:28 imx6ull-microgea chat[667]: OK
Nov 19 17:27:28 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:28 imx6ull-microgea chat[667]: send (AT^M)
Nov 19 17:27:28 imx6ull-microgea chat[667]: expect (OKd)
Nov 19 17:27:28 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:28 imx6ull-microgea chat[667]: AT^M^M
Nov 19 17:27:28 imx6ull-microgea chat[667]: OK^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: alarm
Nov 19 17:27:31 imx6ull-microgea chat[667]: send (AT^M)
Nov 19 17:27:31 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:31 imx6ull-microgea chat[667]: AT^M^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: OK
Nov 19 17:27:31 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:31 imx6ull-microgea chat[667]: send (ATI^M)
Nov 19 17:27:31 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:31 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: ATI^M^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: Manufacturer: SIMCOM INCORPORATED^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: Model: SIMCOM_SIM7600G^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: Revision: SIM7600M21-A_V2.0.1^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: SVN: 01^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: IMEI: 868822041830553^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: +GCAP: +CGSM^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: OK
Nov 19 17:27:31 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:31 imx6ull-microgea chat[667]: send (AT+CCID^M)
Nov 19 17:27:31 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:31 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: AT+CCID^M^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: +CCID: 8939104450022422961^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: OK
Nov 19 17:27:31 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:31 imx6ull-microgea chat[667]: send (ATZ^M)
Nov 19 17:27:31 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:31 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: ATZ^M^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: OK
Nov 19 17:27:31 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:31 imx6ull-microgea chat[667]: send (ATQ0 V1 E1 S0=0^M)
Nov 19 17:27:31 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:31 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: ATQ0 V1 E1 S0=0^M^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: OK
Nov 19 17:27:31 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:31 imx6ull-microgea chat[667]: send (AT^M)
Nov 19 17:27:31 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:31 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: AT^M^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: OK
Nov 19 17:27:31 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:31 imx6ull-microgea chat[667]: send (AT+CGDCONT=1,"IP","mobile.vodafone.it"^M)
Nov 19 17:27:31 imx6ull-microgea chat[667]: expect (OK)
Nov 19 17:27:31 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: AT+CGDCONT=1,"IP","mobile.vodafone.it"^M^M
Nov 19 17:27:31 imx6ull-microgea chat[667]: OK
Nov 19 17:27:31 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:31 imx6ull-microgea chat[667]: send (ATDT*99***1#^M)
Nov 19 17:27:32 imx6ull-microgea chat[667]: timeout set to 30 seconds
Nov 19 17:27:32 imx6ull-microgea chat[667]: expect (CONNECT)
Nov 19 17:27:32 imx6ull-microgea chat[667]: ^M
Nov 19 17:27:32 imx6ull-microgea chat[667]: ATDT*99***1#^M^M
Nov 19 17:27:32 imx6ull-microgea chat[667]: CONNECT
Nov 19 17:27:32 imx6ull-microgea chat[667]:  -- got it
Nov 19 17:27:32 imx6ull-microgea chat[667]: send (^M)
Nov 19 17:27:32 imx6ull-microgea pppd[532]: Script /usr/sbin/chat -v -t15 -f /etc/ppp/chatscripts/mobile-modem.chat finished (pid 667), status = 0x0
Nov 19 17:27:32 imx6ull-microgea pppd[532]: Serial connection established.
Nov 19 17:27:32 imx6ull-microgea pppd[532]: using channel 10
Nov 19 17:27:32 imx6ull-microgea connmand[461]: ppp0 {create} index 15 type 512 <PPP>
Nov 19 17:27:32 imx6ull-microgea connmand[461]: ppp0 {update} flags 4240 <DOWN>
Nov 19 17:27:32 imx6ull-microgea connmand[461]: ppp0 {newlink} index 15 address 00:00:00:00:00:00 mtu 1500
Nov 19 17:27:32 imx6ull-microgea connmand[461]: ppp0 {newlink} index 15 operstate 2 <DOWN>
Nov 19 17:27:32 imx6ull-microgea pppd[532]: Using interface ppp0
Nov 19 17:27:32 imx6ull-microgea pppd[532]: Connect: ppp0 <--> /dev/ttyUSB2
Nov 19 17:27:33 imx6ull-microgea pppd[532]: sent [LCP ConfReq id=0xa <asyncmap 0x0> <magic 0x4ea61b56> <pcomp> <accomp>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: rcvd [LCP ConfReq id=0x24 <asyncmap 0x0> <auth chap MD5> <magic 0xd0ec14e7> <pcomp> <accomp>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: No auth is possible
Nov 19 17:27:33 imx6ull-microgea pppd[532]: sent [LCP ConfRej id=0x24 <auth chap MD5>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: rcvd [LCP ConfAck id=0xa <asyncmap 0x0> <magic 0x4ea61b56> <pcomp> <accomp>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: rcvd [LCP ConfReq id=0x25 <asyncmap 0x0> <magic 0xd0ec14e7> <pcomp> <accomp>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: sent [LCP ConfAck id=0x25 <asyncmap 0x0> <magic 0xd0ec14e7> <pcomp> <accomp>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: sent [LCP EchoReq id=0x0 magic=0x4ea61b56]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: sent [CCP ConfReq id=0xa <deflate 15> <deflate(old#) 15> <bsd v1 15>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: sent [IPCP ConfReq id=0xa <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: sent [IPV6CP ConfReq id=0xa <addr fe80::7d35:27cf:b727:e7aa>]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: rcvd [LCP DiscReq id=0x26 magic=0xd0ec14e7]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: rcvd [LCP EchoRep id=0x0 magic=0xd0ec14e7 4e a6 1b 56]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: rcvd [LCP ProtRej id=0x27 80 fd 01 0a 00 0f 1a 04 78 00 18 04 78 00 15 03 2f]
Nov 19 17:27:33 imx6ull-microgea pppd[532]: Protocol-Reject for 'Compression Control Protocol' (0x80fd) received
Nov 19 17:27:33 imx6ull-microgea pppd[532]: Hangup (SIGHUP)
Nov 19 17:27:33 imx6ull-microgea pppd[532]: Modem hangup
Nov 19 17:27:33 imx6ull-microgea pppd[532]: Connection terminated.
Nov 19 17:27:33 imx6ull-microgea connmand[461]: ppp0 {dellink} index 15 operstate 2 <DOWN>
Nov 19 17:27:33 imx6ull-microgea connmand[461]: (null) {RX} 0 packets 0 bytes
Nov 19 17:27:33 imx6ull-microgea connmand[461]: (null) {TX} 3 packets 51 bytes
Nov 19 17:27:33 imx6ull-microgea connmand[461]: (null) {remove} index 15

It keeps looping on these instructions forever. Has anyone ever faced this problem? How do you solve it?

I've already tried with different apn like web.omnitel.it or wap.omintel.it as some guides online suggest but they didn't work. I also tried with

AT+CGDCONT=2,"IP","mobile.vodafone.it"

because I saw a similar question online but it didn't work. I also tried to test the process in a different room because sometimes in our office Vodafone doesn't work well but nothing changed.

Is the SIM activated? Does it have a decent signal (check with AT command)? In my experience, failing to confirm these two things is the biggest reason for the PPP network dial-in to fail. — thelummox, Feb 28 '23 at 14:48
`at+cpin?` gives me `+CPIN: READY` so I think the SIM is activated. `at+csq` gives me `+CSQ: 99,99` in every room of the office. 99 should be a detection error but I don't know how to solve it and I can't check it outside the office. — dod0bob, Feb 28 '23 at 15:01
`AT+CPIN?` is the status of some password for the device to operate. It doesn't tell you if it's registered on a network. `AT+CREG?` will show the network registration status. I'd check that first. `AT+CSQ` is telling you it can't detect a signal. Maybe you need a better antenna? — thelummox, Feb 28 '23 at 18:46
For some reasons `AT+CUSBPIDSWITCH=9018,1,1` on `/dev/ttyUSB2` works and now I can connect to internet and send packages. This command isn't mentioned on any guide I read. It also works on reboot, I've just need to turn on the modem with some commands. — dod0bob, Mar 01 '23 at 08:58
I'm not familiar with that AT command. It must be modem-specific. But, if it works, it works. — thelummox, Mar 02 '23 at 15:06

pppd problem: Hangup (SIGHUP) after Protocol-Reject

0 Answers0