When using pppd with Linux using chatscripts there is an error with AT commands in establishing the connection because of /d/c not included in the CONNECT string of the chatscript file.
It is always better to use the script file generated by the PPPConfig utility for PPP connection with Linux using chatscripts as there would be problems in connection because sometimes the CONNECT string might not include /d/c while using other script files. The chatscript file generated by PPPConfig might looks as below:
This chatfile was generated by pppconfig 2.3.18.
Please do not delete any of the comments. Pppconfig needs them.
ispauth CHAP
abortstring
ABORT BUSY ABORT ‘NO CARRIER’ ABORT VOICE ABORT ‘NO DIALTONE’ ABORT ‘NO DIAL TONE’ ABORT ‘NO ANSWER’ ABORT DELAYED
modeminit
‘’ ATZ
ispnumber
OK-AT-OK “ATDT99**1#”
ispconnect
CONNECT /d/c
prelogin
ispname
isppassword
postlogin
end of pppconfig stuff
Options file:
debug
/dev/ttyACM0
115200
modem
crtscts
defaultroute
noipdefault
user
password
#interface ppp0
linkname ppp0
connect “/usr/sbin/chat -v -f /etc/chatscripts/airtel”.