ISDN Pro TA a podivne odpojenie

[Mikes Mario]

Stav:
jadro RH 7.0 2.2.19-7.0.1
modem ISDN 3Com Pro TA pripojeny na USB
Via Apollo Pro chipset
moduly usbcore,uhci,acm

Po pripojeni sa prenos realizuje v poriadku ale do 10 minut modem
nepravidelne zavesi. pppd bezi dalej, ifconfig ukazuje narast paketov na
ppp0. Modem nesignalizuje ziadny prenos LED-kami a je ocividne odpojeny.
V logoch nieje ziadna zmienka o problemoch po pripojeni linky. Pri
inicializacii usb sa loguje:
...
kernel: usb.c: registered new driver usbdevfs
kernel: usb.c: registered new driver hub
kernel: uhci.c: USB UHCI at I/O 0xe400, IRQ 12
kernel: uhci.c: detected 2 ports
kernel: usb.c: new USB bus registered, assigned bus number 1
kernel: usb.c: USB new device connect, assigned device number 1
kernel: hub.c: USB hub found
kernel: hub.c: 2 ports detected
kernel: usb.c: registered new driver acm
kernel: usb.c: USB new device connect, assigned device number 2
kernel: ttyACM0: USB ACM device
kernel: hub.c: already running port 1 disabled by hub (EMI?),
re-enabling...
????
kernel: usb.c: USB disconnect on device 2
kernel: usb.c: USB new device connect, assigned device number 2
kernel: ttyACM0: USB ACM device
...

Vie mi niekto poradit preco sa modem pripaja a odpaja na 2 portoch?
Preco sa pppd nedozvie o odpojeni modemu ?

Dakujem