FC3: ISDN connection

[activecs]

My ISDN connection uses an external usb device, as below. This has
worked with FC2, with it referring to it as /dev/input/ttyACM0.
If I understand correctly, I need to create a "rule" for it in
/etc/udev/rules.d and call the file something like 20-udev.rules.
However, I don't really understand what it should contain, and haven't
made it recognise it as the device for my internet connection. could
anyone help me with this?
Thanks.

Relevant section of /proc/bus/usb/devices
 
T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  2 Spd=12  MxCh= 0
D:  Ver= 1.10 Cls=02(comm.) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=0aca ProdID=1060 Rev= 0.11
S:  Manufacturer=OPEN Networks Ltd
S:  Product=OPEN NT1 Plus II
C:* #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=  0mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=(none)
E:  Ad=81(I) Atr=03(Int.) MxPS=  16 Ivl=128ms
I:  If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=(none)
E:  Ad=02(O) Atr=02(Bulk) MxPS=  32 Ivl=0ms
E:  Ad=83(I) Atr=02(Bulk) MxPS=  32 Ivl=0ms

DP
South Australia