ISDN Question?

[ashrafkadry]

Hi

I have two questions regarding ISDN connectivity,FirstWhat privilage does an external ISDN modem has over an internal one,even if the internal was USB connected, and the second one is What's the difference between a U and a S/T interface for a ISDN NTU unit, given that I live in Egypt and not in the U.S, SO is a the S/T interface needed here in Egypt or not (Okay, okay, three questions are too much)

Best Regards
Ashraf Mohammed

 

[Horsepower]

From Cisco:

"S/T-interface: A four-wire ISDN circuit. The S/T interface is the part
of a ISDN line that connects to the
terminal equipment. In North America, if your router has an S/T
interface it requires an external NT-1 to
connect to the Telco network. In the rest of the world, an NT-1 is not
required in the customer premises.

U-interface: A two-wire ISDN circuit - essentially today's standard one
pair telephone company local loop
made of twisted-wire. The U interface is the most common ISDN interface
(in North America) and extends
from the central office."