Difficulties to establish a ppp connection to a GSM provider

I want to establish a ppp link to a GSM provider with my cell phone modem. The modem gets recognized and I can send AT commands just fine, but I can not get the connection established. My chat script looks like: ####################################### SAY 'Setting the abort string\n' SAY '\n' # Abort String ------------------------------ ABORT 'NO DIAL TONE' ABORT 'NO ANSWER' ABORT 'NO CARRIER' ABORT DELAYED ####################################### SAY 'Initializing modem\n' # Modem Initialization '' AT OK ATZ ####################################### SAY '\n' SAY 'Setting APN\n' # Access Point Name (APN) # Incorrect APN or CGDCONT can often cause errors in connection. # Below are a bunch of different popular APNs #REG:\s1 AT+cgdcont=1,"IP","proxy" #OK 'AT+CGDCONT=0,"IP","proxy"' #OK 'AT+CGDCONT=1,"IP","proxy"' #OK 'AT+CGDCONT=2,"IP","proxy"' OK 'AT+CGDCONT=1,"IP","m2mstatic.apn"' #OK 'AT+CGDCONT=1,"IP","ISP.TELUS.COM"' #OK 'AT+CGDCONT=1,"IP","INTERNET.COM"' #OK 'AT+CGDCONT=1,"IP","ISP.CINGULAR"' #OK 'AT+CGDCONT=2,"IP","ISP.CINGULAR"' "" And in /var/log/messages I get the following messages: Jan 11 04:08:49 ariag25 pppd: pppd 2.4.5 started by root, uid 0 Jan 11 04:08:50 ariag25 chat: abort on (NO DIAL TONE) Jan 11 04:08:50 ariag25 chat: abort on (NO ANSWER) Jan 11 04:08:50 ariag25 chat: abort on (NO CARRIER) Jan 11 04:08:50 ariag25 chat: abort on (DELAYED) Jan 11 04:08:50 ariag25 chat: send (AT^M) Jan 11 04:08:50 ariag25 chat: expect (OK) Jan 11 04:08:50 ariag25 chat: AT^M^M Jan 11 04:08:50 ariag25 chat: OK Jan 11 04:08:50 ariag25 chat: -- got it Jan 11 04:08:50 ariag25 chat: send (ATZ^M) Jan 11 04:08:51 ariag25 chat: expect (OK) Jan 11 04:08:51 ariag25 chat: ^M Jan 11 04:08:51 ariag25 chat: ATZ^M^M Jan 11 04:08:51 ariag25 chat: OK Jan 11 04:08:51 ariag25 chat: -- got it Jan 11 04:08:51 ariag25 chat: send (AT+CGDCONT=1,"IP","m2mstatic.apn"^M) Jan 11 04:08:51 ariag25 chat: expect (OK) Jan 11 04:08:51 ariag25 chat: ^M Jan 11 04:08:51 ariag25 chat: AT+CGDCONT=1,"IP","m2mstatic.apn"^M^M Jan 11 04:08:51 ariag25 chat: OK Jan 11 04:08:51 ariag25 chat: -- got it Jan 11 04:08:51 ariag25 chat: send (ATDT*99#^M) Jan 11 04:08:51 ariag25 chat: expect (CONNECT) Jan 11 04:08:51 ariag25 chat: ^M Jan 11 04:08:51 ariag25 chat: ATDT*99#^M^M Jan 11 04:08:51 ariag25 chat: CONNECT Jan 11 04:08:51 ariag25 chat: -- got it Jan 11 04:08:51 ariag25 chat: send (^M) Jan 11 04:08:51 ariag25 pppd: Serial connection established. ###Edit I don't think things are wrong with my chat script but my modem instead. Notice that on the bottom of the messages, the context switched from chat to pppd - why is that? May my power supply be too weak? That's what I suspect now. Any ideas? Also, if I do a killall pppd after this and try to connect with screen screen /dev/modem 9600 the modem doesn't reply anymore until I power cycle it. However, I'm surprised! I hooked it up to a 2.1A USB power supply. ###Edit2 My /etc/ppp/options looks like: debug /dev/ttyUSB1 9600 modem crtscts lock connect /etc/ppp/net-connect asyncmap 0 defaultroute and /etc/ppp/peers/provider like this: connect "/usr/sbin/chat -v -f /etc/chatscripts/pap -T *99***1#" # Serial device to which the modem is connected. /dev/modem # Speed of the serial line. 9600 # Assumes that your IP address is allocated dynamically by the ISP. noipdefault # Try to get the name server addresses from the ISP. usepeerdns # Use this connection as the default route. defaultroute # Makes pppd "dial again" when the connection is lost. persist # Do not ask the remote to authenticate. noauth