Yun, 3G dongle and yun_3g library

Official Hardware Classic Yún
12

Thank you everybody for your help!
Now I had some time to have some new tests, and this is what I obtain:

18:45:26 yun kern.info kernel: [   60.220000] usb 1-1.1.2: new high-speed USB device number 6 using ehci-platform
18:45:26 yun user.info sysinit: Generating selfsigned certificate with subject 'C=IT;ST=Turin;L=Turin;CN=Arduino LLC;' and validity 2014-05-03 16:45:25-2038-01-19 03:14:07
18:45:26 yun kern.info kernel: [   60.340000] usb 1-1.1.2: New USB device found, idVendor=19d2, idProduct=0064
18:45:26 yun kern.info kernel: [   60.340000] usb 1-1.1.2: New USB device strings: Mfr=2, Product=1, SerialNumber=0
18:45:26 yun kern.info kernel: [   60.340000] usb 1-1.1.2: Product: ZTE CDMA Technologies MSM
18:45:26 yun kern.info kernel: [   60.350000] usb 1-1.1.2: Manufacturer: ZTE,Incorporated
18:45:26 yun kern.info kernel: [   60.370000] usbserial_generic 1-1.1.2:1.0: GSM modem (1-port) converter detected
18:45:26 yun kern.info kernel: [   60.370000] usb 1-1.1.2: GSM modem (1-port) converter now attached to ttyUSB0
18:45:26 yun kern.info kernel: [   60.380000] scsi2 : usb-storage 1-1.1.2:1.1
18:45:26 yun kern.info kernel: [   60.380000] usbserial_generic 1-1.1.2:1.2: GSM modem (1-port) converter detected
18:45:26 yun kern.info kernel: [   60.380000] usb 1-1.1.2: GSM modem (1-port) converter now attached to ttyUSB1
18:45:27 yun user.notice firewall: Reloading firewall due to ifup of lan (wlan0)
18:45:28 yun kern.notice kernel: [   61.690000] scsi 2:0:0:0: Direct-Access     ZTE      MMC Storage      2.31 PQ: 0 ANSI: 2
18:45:28 yun kern.notice kernel: [   61.930000] sd 2:0:0:0: [sdb] Attached SCSI removable disk
18:45:29 yun user.info sysinit: Unknown group "netdev" in message bus configuration file
18:45:30 yun user.notice dnsmasq: DNS rebinding protection is active, will discard upstream RFC1918 responses!
18:45:30 yun user.notice dnsmasq: Allowing 127.0.0.0/8 responses
18:45:30 yun daemon.info dnsmasq[1190]: started, version 2.66 cachesize 150
18:45:30 yun daemon.info dnsmasq[1190]: compile time options: IPv6 GNU-getopt no-DBus no-i18n no-IDN DHCP no-DHCPv6 no-Lua TFTP no-conntrack no-ipset no-auth
18:45:30 yun daemon.info dnsmasq[1190]: using local addresses only for domain lan
18:45:30 yun daemon.info dnsmasq[1190]: reading /tmp/resolv.conf.auto
18:45:30 yun daemon.info dnsmasq[1190]: using nameserver 88.149.128.12#53
18:45:30 yun daemon.info dnsmasq[1190]: using nameserver 88.149.128.22#53
18:45:30 yun daemon.info dnsmasq[1190]: using local addresses only for domain lan
18:45:30 yun daemon.info dnsmasq[1190]: read /etc/hosts - 1 addresses
18:45:31 yun daemon.info avahi-daemon[1196]: Found user 'nobody' (UID 65534) and group 'nogroup' (GID 65534).
18:45:31 yun daemon.info avahi-daemon[1196]: Successfully dropped root privileges.
18:45:31 yun daemon.info avahi-daemon[1196]: avahi-daemon 0.6.31 starting up.
18:45:31 yun daemon.warn avahi-daemon[1196]: WARNING: No NSS support for mDNS detected, consider installing nss-mdns!
18:45:31 yun daemon.info avahi-daemon[1196]: Loading service file /etc/avahi/services/arduino.service.
18:45:31 yun daemon.info avahi-daemon[1196]: Loading service file /etc/avahi/services/ssh.service.
18:45:31 yun daemon.info avahi-daemon[1196]: Joining mDNS multicast group on interface wlan0.IPv4 with address 192.168.0.29.
18:45:31 yun daemon.info avahi-daemon[1196]: New relevant interface wlan0.IPv4 for mDNS.
18:45:31 yun daemon.info avahi-daemon[1196]: Network interface enumeration completed.
18:45:31 yun daemon.info avahi-daemon[1196]: Registering new address record for 192.168.0.29 on wlan0.IPv4.
18:45:31 yun daemon.info avahi-daemon[1196]: Registering HINFO record with values 'MIPS'/'LINUX'.
18:45:32 yun user.info sysinit: Start uSDaemon
18:45:32 yun daemon.info avahi-daemon[1196]: Server startup complete. Host name is yun.local. Local service cookie is 1209727940.
18:45:33 yun daemon.info avahi-daemon[1196]: Service "Secure Shell on yun" (/etc/avahi/services/ssh.service) successfully established.
18:45:33 yun daemon.info avahi-daemon[1196]: Service "yun" (/etc/avahi/services/arduino.service) successfully established.
18:45:40 yun authpriv.info dropbear[1281]: Child connection from 192.168.0.2:37807
19:00:16 yun authpriv.info dropbear[1281]: Exit before auth: Timeout before auth
19:00:20 yun authpriv.info dropbear[1387]: Child connection from 192.168.0.2:37810
19:00:28 yun authpriv.notice dropbear[1387]: Password auth succeeded for 'root' from 192.168.0.2:37810
19:00:29 yun user.notice usb-modeswitch: 1-1.1.2:1.0: Manufacturer=ZTE,Incorporated Product=ZTE_CDMA_Technologies_MSM Serial=?
19:00:29 yun user.notice usb-modeswitch: 1-1.1.2:1.1: Manufacturer=ZTE,Incorporated Product=ZTE_CDMA_Technologies_MSM Serial=?
19:00:29 yun user.notice usb-modeswitch: 1-1.1.2:1.2: Manufacturer=ZTE,Incorporated Product=ZTE_CDMA_Technologies_MSM Serial=?
19:00:30 yun daemon.notice netifd: wan2 (1801): comgt 19:00:30 -> -- Error Report --
19:00:30 yun daemon.notice netifd: wan2 (1801): comgt 19:00:30 -> ---->              ^
19:00:30 yun daemon.notice netifd: wan2 (1801): comgt 19:00:30 -> Error @114, line 9, Could not write to COM device. (1)
19:00:30 yun daemon.notice netifd: wan2 (1801): 
19:00:32 yun daemon.notice netifd: wan2 (1801): Trying to set PIN
19:00:33 yun daemon.notice netifd: wan2 (1801): PIN set successfully
19:00:33 yun daemon.notice pppd[1894]: pppd 2.4.5 started by root, uid 0
19:00:34 yun local2.info chat[1898]: abort on (BUSY)
19:00:34 yun local2.info chat[1898]: abort on (NO CARRIER)
19:00:34 yun local2.info chat[1898]: abort on (ERROR)
19:00:34 yun local2.info chat[1898]: report (CONNECT)
19:00:34 yun local2.info chat[1898]: timeout set to 10 seconds
19:00:34 yun local2.info chat[1898]: send (AT&F^M)
19:00:34 yun local2.info chat[1898]: expect (OK)
19:00:34 yun local2.info chat[1898]: ^M
19:00:34 yun local2.info chat[1898]: +ZDONR: "Not Found"^M
19:00:34 yun local2.info chat[1898]: ^M
19:00:34 yun local2.info chat[1898]: +ZPASR: "No Service"^M
19:00:34 yun local2.info chat[1898]: AT&F^M^M
19:00:34 yun local2.info chat[1898]: OK
19:00:34 yun local2.info chat[1898]:  -- got it
19:00:34 yun local2.info chat[1898]: send (ATE1^M)
19:00:34 yun local2.info chat[1898]: expect (OK)
19:00:34 yun local2.info chat[1898]: ^M
19:00:34 yun local2.info chat[1898]: ATE1^M^M
19:00:34 yun local2.info chat[1898]: OK
19:00:34 yun local2.info chat[1898]:  -- got it
19:00:34 yun local2.info chat[1898]: send (AT+CGDCONT=1,"IP","tre.it"^M)
19:00:34 yun local2.info chat[1898]: send (AT+SYSCFG=2,2,3FFFFFFF,0,4^M)
19:00:35 yun local2.info chat[1898]: timeout set to 30 seconds
19:00:35 yun local2.info chat[1898]: expect (OK)
19:00:35 yun local2.info chat[1898]: ^M
19:00:35 yun local2.info chat[1898]: AT+CGDCONT=1,"IP","tre.it"^M^M
19:00:35 yun local2.info chat[1898]: OK
19:00:35 yun local2.info chat[1898]:  -- got it
19:00:35 yun local2.info chat[1898]: send (ATD*99#^M)
19:00:35 yun local2.info chat[1898]: expect (CONNECT)
19:00:35 yun local2.info chat[1898]: ^M
19:00:35 yun local2.info chat[1898]: AT+SYSCFG=2,2,3FFFFFFF,0,4^M^M
19:00:35 yun local2.info chat[1898]: ERROR
19:00:35 yun local2.info chat[1898]:  -- failed
19:00:35 yun local2.info chat[1898]: Failed (ERROR)
19:00:35 yun daemon.err pppd[1894]: Connect script failed
19:00:46 yun daemon.info pppd[1894]: Exit.
19:00:46 yun daemon.notice netifd: Interface 'wan2' is now down
19:02:24 yun daemon.notice netifd: wan2 (1968): comgt 19:02:24 -> -- Error Report --
19:02:24 yun daemon.notice netifd: wan2 (1968): comgt 19:02:24 -> ---->                   ^
19:02:24 yun daemon.notice netifd: wan2 (1968): comgt 19:02:24 -> Error @152, line 10, Could not write to COM device. (1)
19:02:24 yun daemon.notice netifd: wan2 (1968):

So: it connects, or it seems to do, but it gets an error I can't understand, concerning AT commands and the script generated by linino_set3g.ino from PicTux

/bin/cat <<EOF > $TGCHAT
ABORT BUSY
ABORT 'NO CARRIER'
ABORT ERROR
REPORT CONNECT
TIMEOUT 10
"" "AT&F"
OK "ATE1"
OK 'AT+CGDCONT=1,"IP","\$USE_APN"'
SAY "Calling UMTS/EDGE/GPRS"
TIMEOUT 30
OK "ATD*99#"
CONNECT ''
EOF

I compared PicTux works with some guides I found online, and as far as I understand there aren't significant differences:

and

By now I don't know what to do...please help!