Allora ho lanciato i seguenti comandi ed ho ottenuto questo:
tobler749@tobler749-laptop:~$ tail -f /var/log/messages
Apr 21 23:53:56 tobler749-laptop kernel: [ 3319.648191] usb 3-1: USB disconnect, address 4
Apr 21 23:53:56 tobler749-laptop kernel: [ 3319.648458] pl2303 ttyUSB1: pl2303 converter now disconnected from ttyUSB1
Apr 21 23:53:56 tobler749-laptop kernel: [ 3319.648489] pl2303 3-1:1.0: device disconnected
Apr 21 23:53:57 tobler749-laptop kernel: [ 3321.324052] usb 2-1: new full speed USB device using uhci_hcd and address 6
Apr 21 23:53:58 tobler749-laptop kernel: [ 3321.486248] usb 2-1: configuration #1 chosen from 1 choice
Apr 21 23:53:58 tobler749-laptop kernel: [ 3321.492864] pl2303 2-1:1.0: pl2303 converter detected
Apr 21 23:53:58 tobler749-laptop kernel: [ 3321.508174] usb 2-1: pl2303 converter now attached to ttyUSB0
Apr 21 23:56:40 tobler749-laptop kernel: [ 3484.320100] usb 2-1: USB disconnect, address 6
Apr 21 23:56:40 tobler749-laptop kernel: [ 3484.320367] pl2303 ttyUSB0: pl2303 converter now disconnected from ttyUSB0
Apr 21 23:56:40 tobler749-laptop kernel: [ 3484.320399] pl2303 2-1:1.0: device disconnected
Apr 21 23:56:57 tobler749-laptop kernel: [ 3500.464049] usb 2-1: new full speed USB device using uhci_hcd and address 7
Apr 21 23:56:57 tobler749-laptop kernel: [ 3500.627232] usb 2-1: configuration #1 chosen from 1 choice
Apr 21 23:56:57 tobler749-laptop kernel: [ 3500.632558] pl2303 2-1:1.0: pl2303 converter detected
Apr 21 23:56:57 tobler749-laptop kernel: [ 3500.651152] usb 2-1: pl2303 converter now attached to ttyUSB0

Una volta collegato l'adattatore il messaggio di connessione esce.
Poi ho lanciato lsusb ed ottengo questo

tobler749@tobler749-laptop:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 002: ID 1241:1166 Belkin MI-2150 Trust Mouse
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 007: ID 0557:2008 ATEN International Co., Ltd UC-232A Serial Port [pl2303]

Alla fine ho lanciato minicom -s ed ho modificato cosi:

+-----------------------------------------------------------------------+
| A - Serial Device : /dev/ttyUSB0 |
| B - Lockfile Location : /var/lock |
| C - Callin Program : |
| D - Callout Program : |
| E - Bps/Par/Bits : 115200 5N1 |
| F - Hardware Flow Control : Yes |
| G - Software Flow Control : No |
| |
| Change which setting? |
+-----------------------------------------------------------------------+
| Screen and keyboard |
| Save setup as dfl |
| Save setup as.. |
| Exit |
| Exit from Minicom |
+--------------------------+
esco da minicom salvo mi dice inizializzazione modem,ma non riesco ancora a farlo andare con il software. Sul pc desktop che ho di sopra che ha gia la seriale nella scheda madre nessun problema funziona benissimo,è sul portatile che mi fa impazzire.

Per finire ottengo questo:

Welcome to minicom 2.3

OPTIONS: I18n
Compiled on Sep 25 2009, 23:40:20.
Port /dev/ttyUSB0

Press CTRL-A Z for help on special keys

Ho anche modificato i permessi di ttyUSB0 dandogli lettura scrittura a tutti.

Datemi una mano per favore solo voi esperti ci potete riuscire.

Vi ringrazio tantissimo.