It may not be exactly equivalent but below is what's in the PPP chat script for my Linux laptop connecting to GPRS on an old Nokia 6310i on Vodafone.

As you can see, in the AT+CGDCONT line, the string after "IP" is "internet" rather than an operator's domain name.

My N800 will also connect via same phone however I haven't looked at the log files to see what it sends.

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SAY "Press CTRL-C to close the connection at any stage!" \
SAY "\ndefining PDP context...\n" \
OK ATH \
OK ATE1 \
OK 'AT+CGDCONT=1,"IP","internet","",0,0' \
OK ATD*99# \
TIMEOUT 22 \
SAY "\nwaiting for connect...\n" \
CONNECT "" \
SAY "\nConnected." \
SAY "\nIf the following ppp negotiations fail,\n" \
SAY "try restarting the phone.\n"