3G connection with wvdial gets no IP, exits with code 16

I am trying to establish a 3G connection with Raspbian, a 3G USB dongle, usb_modeswitch and wvdial. I followed this tutorial which has worked well before with a different 3G dongle. My 3G dongle is a ZTE D6601, the SIM has no PIN and the connection works flawlessly with the ISPs tool under Windows and under Ubuntu 15 with the built-in mobile broadband tool. But I need to do this on a Raspberry Pi and from the command line. This is what I have tried so far: When I boot Raspbian, lsusb returns Bus 001 Device 004: ID 19d2:0154 ZTE WCDMA Technologies MSM I then run sudo usb_modeswitch -I -v 19d2 -p 0154 -c /etc/usb_modeswitch.conf Which changes the ProductID to Bus 001 Device 009: ID 19d2:0108 ZTE WCDMA Technologies MSM There is more than one 3G dongle with 0154 as DefaultProduct ID so the standard switching rules of usb_modeswitch don't work. 0108 is what Ubuntu switches the device to or what happens when I sudo eject the virtual CD drive, so I used that. My /etc/network/interfaces was only changed to use a WiFi connection: auto lo iface lo inet loopback iface eth0 inet dhcp allow-hotplug wlan0 iface wlan0 inet manual wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf iface default inet dhcp So far, so good. When I run sudo wvdialconf, a modem is detected at /dev/ttyUSB1. I then run sudo wvdial dcom with dcom being defined like this (APN "e-connect" is correct, no user / pass required): [Dialer dcom] Modem = /dev/ttyUSB1 Init1 = ATZ Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 Init3 = AT+CGDCONT=1,"IP","e-connect" Stupid Mode = 1 Modem Type = Analog Modem Phone = *99# ISDN = 0 Username = { } Auto Reconnect = 1 Password = { } Baud = 460800 The shell returns this: --> WvDial: Internet dialer version 1.61 --> Initializing modem. --> Sending: ATZ OK --> Sending: ATZ OK --> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 OK --> Sending: AT+CGDCONT=1,"IP","e-connect" AT+CGDCONT=1,"IP","e-connect" OK --> Modem initialized. --> Sending: ATDT*99# --> Waiting for carrier. ATDT*99# CONNECT 21600000 --> Carrier detected. Starting PPP immediately. --> Starting pppd at Sat Apr 25 18:09:08 2015 --> Pid of pppd: 5530 --> Using interface ppp0 --> pppd: FX�FX8GXp Disconnecting at Sat Apr 25 18:09:39 2015 --> The PPP daemon has died: A modem hung up the phone (exit code = 16) --> man pppd explains pppd error codes in more detail. --> Try again and look into /var/log/messages and the wvdial and pppd man pages for more information. --> Auto Reconnect will be attempted in 5 seconds --> Initializing modem. --> Sending: ATZ ATZ OK --> Sending: ATZ ATZ OK --> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 OK --> Sending: AT+CGDCONT=1,"IP","e-connect" AT+CGDCONT=1,"IP","e-connect" OK --> Modem initialized. --> Initializing modem. --> Sending: ATZ ATZ OK --> Sending: ATZ ATZ OK --> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 OK --> Sending: AT+CGDCONT=1,"IP","e-connect" AT+CGDCONT=1,"IP","e-connect" OK --> Modem initialized. --> Sending: ATDT*99# --> Waiting for carrier. ATDT*99# ERROR --> Invalid dial command. --> Disconnecting at Sat Apr 25 18:09:45 2015 If I run wvdial dcom again, it will repeat the output of the second connection attempt above (Invalid dial command) and not even configure ppp0. Weirdly, after a quick sudo wvdialconf (during which /etv/wvdial.conf remains unchanged), I can connect again, but it will again assign no IP and break after 10 seconds. I have replicated this several times. Maybe this is also interesting: wlan0 loses its IP the moment ppp0 is created and I can only get it back running sudo ifdown wlan0 and sudo ifup wlan0 even though it is set to automatically reconnect.