I have an RS485 modem that I connected to my computer using a USB to RS485 converter. I can connect to it using Minicom with a baud rate of 9600, 8N1, and xonxoff flow control settings. The modem responds to AT commands.
I have tried configuring pppd and chat settings, but only the chat settings execute correctly.I tried setting the MTU and MRU values between 550 and 1500, but unfortunately, I couldn't get it to work with these values either.
I'm running out of ideas.How can I get more meaningful logs to understand why I'm not getting a response?
sudo pppd call quectel-ppppppd options in effect:debug # (from /etc/ppp/peers/quectel-ppp)kdebug 1 # (from /etc/ppp/peers/quectel-ppp)nodetach # (from /etc/ppp/peers/quectel-ppp)dump # (from /etc/ppp/peers/quectel-ppp)noauth # (from /etc/ppp/peers/quectel-ppp)/dev/ttyUSB0 # (from /etc/ppp/peers/quectel-ppp)9600 # (from /etc/ppp/peers/quectel-ppp)lock # (from /etc/ppp/peers/quectel-ppp)connect /usr/sbin/chat -s -v -f /etc/ppp/peers/quectel-chat-connect # (from /etc/ppp/peers/quectel-ppp)disconnect /usr/sbin/chat -s -v -f /etc/ppp/peers/quectel-chat-disconnect # (from /etc/ppp/peers/quectel-ppp)xonxoff # (from /etc/ppp/peers/quectel-ppp)local # (from /etc/ppp/peers/quectel-ppp)mru 1492 # (from /etc/ppp/peers/quectel-ppp)mtu 1492 # (from /etc/ppp/peers/quectel-ppp)lcp-restart 6 # (from /etc/ppp/peers/quectel-ppp)novj # (from /etc/ppp/peers/quectel-ppp)novjccomp # (from /etc/ppp/peers/quectel-ppp)ipcp-accept-local # (from /etc/ppp/peers/quectel-ppp)ipcp-accept-remote # (from /etc/ppp/peers/quectel-ppp)noipdefault # (from /etc/ppp/peers/quectel-ppp)defaultroute # (from /etc/ppp/peers/quectel-ppp)usepeerdns # (from /etc/ppp/peers/quectel-ppp)noccp # (from /etc/ppp/peers/quectel-ppp)abort on (BUSY)abort on (NO CARRIER)abort on (NO DIALTONE)abort on (ERROR)abort on (NO ANSWER)timeout set to 120 secondssend (AT^M)expect (OK)^MOKOK -- got itsend (ATE0^M)expect (OK)^M^MOKOK -- got itsend (ATI^M)expect (OK)^M^MQuectelQuectel^MEG915NEG915N^MRevision: EG915NEUAGR03A09M16Revision: EG915NEUAGR03A09M16^M^MOKOK -- got itsend (AT+CSQ^M)expect (OK)^M^M+CSQ: 22,99+CSQ: 22,99^M^MOKOK -- got itsend (AT+CPIN?^M)expect (OK)^M^M+CPIN: READY+CPIN: READY^M^MOKOK -- got itsend (AT+COPS?^M)expect (OK)^M^M+COPS: 0,2,"21630",7+COPS: 0,2,"21630",7^M^MOKOK -- got itsend (AT+CGREG?^M)expect (OK)^M^M+CGREG: 2,1,"2EE1","B6F06",7+CGREG: 2,1,"2EE1","B6F06",7^M^MOKOK -- got itsend (ATZ^M)expect (OK)^M^MOKOK -- got itsend (AT+CGDCONT=1,"IP","internet.telekom",,0,0^M)expect (OK)AT+CGDCONT=1,"IP","internet.telekom",,0,0^MAT+CGDCONT=1,"IP","internet.telekom",,0,0^M^MOKOK -- got itsend (ATD*99#^M)expect (CONNECT)ATD*99#^MATD*99#^M^MCONNECTCONNECT -- got itPPPD
Using interface ppp0Connect: ppp0 <--> /dev/ttyUSB0sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]sent [LCP ConfReq id=0x1 <mru 1492> <asyncmap 0xa0000> <magic 0x16ea0a07> <pcomp> <accomp>]LCP: timeout sending Config-RequestsConnection terminated.abort on (ERROR)abort on (NO DIALTONE)\send (+++ATH^M)I looked at the following forum posts:https://forums.quectel.com/t/quectel-ec25-ppp-connect-failure/3379/6http://web.mit.edu/~linux/redhat/docs/untarred/PPP-Client-HOWTO-13.html
quectel-ppp
noauthconnect '/usr/sbin/chat -s -v -f /etc/ppp/peers/quectel-chat-connect'disconnect '/usr/sbin/chat -s -v -f /etc/ppp/peers/quectel-chat-disconnect'debug/dev/ttyUSB09600defaultroutenoipdefaultnovjnovjccompnoccpipcp-accept-localipcp-accept-remotelocallockdumpkdebug 1nodetach# Hardware flow control#nocrtscts# Software flow controlxonxoffusepeerdnslcp-restart 6mtu 1492mru 1492/etc/ppp/peers/quectel-chat-connect:
ABORT 'BUSY'ABORT 'NO CARRIER'ABORT 'NO DIALTONE'ABORT 'ERROR'ABORT 'NO ANSWER'TIMEOUT 120ECHO ON'' ATOK ATE0OK ATIOK AT+CSQOK AT+CPIN?OK AT+COPS?OK AT+CGREG?OK ATZOK AT+CGDCONT=1,"IP","internet.telekom",,0,0OK ATD*99#CONNECT