GeorgeVita Using ZTE MF636 with various UBUNTU versions Below you can find some notes ("test results?") about using the ZTE MF636 on various versions of Ubuntu. The ZTE MF636 3G modem responds by default as an autorun CD drive (ZeroCD) or as the internal USB hub (from terminal: lsusb shows 19d2:2000). In order to be used as the actual modem we can follow various methods such as eject the ZeroCD, run usb_modeswitch or issue the command AT+ZCDRUN=8 via a serial communication program (then usuful respond to the lsusb is 19d2:0031). Each method has advantages and problems, requiring more or less user knowledge. All new kernels (up to 2.6.30-rc7) or Ubuntu versions (till the recent 9.04) have NOT managed to work well with this modem series (MF626, 627, ..., 636). Scope of this note is to summarize the "default" bahavior of this modem tested on LiveCD versions of Ubuntu. ---------- Boot from 7.10 desktop LiveCD uname -a Linux ubuntu 2.6.22-14-generic #1 ---------- Attach MF636 lsusb shows 19d2:2000 ZTEMODEM disk appears to desktop eject volume ZTEMODEM disk disappears lsusb shows 19d2:0031 ZTEMODEM disk reappears to desktop leave it there ls /dev/ttyU* shows nothing sudo modprobe usbserial vendor=0x19d2 product=0x0031 ls /dev/ttyU* shows /dev/ttyUSB0 /dev/ttyUSB1 /dev/ttyUSB2 created sudo wvdialconf finds ttyUSB1 and ttyUSB2 useable at 115200 Baud sudo gedit /etc/wvdial.conf with the appropriate data (modem=/dev/ttyUSB2) sudo wvdial and we are connected! ---------- ---------- Boot from 8.04 desktop LiveDVD uname -a Linux ubuntu 2.6.24-16-generic #1 ---------- Attach MF636 lsusb shows 19d2:2000 >>> ZTEMODEM disk NOT appears >>> but a line of dmesg says "sr2 Attached scsi CD-ROM sr2" eject sr2 lsusb shows 19d2:0031 ls /dev/ttyU* shows nothing sudo modprobe usbserial vendor=0x19d2 product=0x0031 ls /dev/ttyU* shows /dev/ttyUSB0 /dev/ttyUSB1 /dev/ttyUSB2 created sudo wvdialconf finds ttyUSB1 and ttyUSB2 useable at 9600 Baud (!) sudo gedit /etc/wvdial.conf with the appropriate data (modem=/dev/ttyUSB2) sudo wvdial and we are connected! ---------- ---------- Boot from 8.10 desktop LiveCD uname -a Linux ubuntu 2.6.27-7-generic #1 ---------- Attach MF636 lsusb shows 19d2:2000 >>> ZTEMODEM disk NOT appears >>> dmesg has a line "usb-storage: device ignored" >>> we cannot eject a "CD drive" manually (drive not shown) >>> modem remains in 19d2:2000 (unuseable state) >>> usbserial cannot be used to create /dev/ttyUSBx >>> we can force the modem to the 19d2:0031 state with >>> AT+ZCDRUN=8 or running usb_modeswitch ---------- ---------- The modem is always useable after the "external" switch to 19d2:0031 with some or more modifications to HAL (add udev rule, edit 10-modem.fdi file). For more info search within ubuntuforums.org ---------- ---------- With the newer 9.04 we cannot use usbserial driver as it is encapsulated to the kernel. You can use the -proposed kernel update till a new one restore this driver externally. Read: http://ubuntuforums.org/showpost.php?p=7302185&postcount=15 Also if you need wvdial and assosiated programs you must install it via Synaptic Package Manager. If you do NOT have an internet connection running on this PC, try "How I restored the missing wvdial (Ubuntu 9.04)" at http://acomelectronics.com/GeorgeVita/restore_wvdial.html More 9.04+ debugging info at: https://bugs.launchpad.net/ubuntu/+source/linux-meta/+bug/373821 Note: All above worked with a valid SIM card inserted into the ZTE MF636 modem with the SIM PIN check disabled and a good 3G signal in my area.