[thelist] Difference between 'S/T' and 'U' ISDN Interfaces?

[Scott Dexter]

> 
> Can anyone enlighten me as to the difference between these 
> two interfaces?  I need to purchase an ISDN gateway/router 
> thingy for my home network, and they seem to come in these 
> two flavors ('S/T' or 'U').  Will either interface work with 
> the ISDN line my telco will be bringing in?

 From Cisco's website (http://www.cisco.com/warp/public/129/27.html):

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.

In other words, get the U-interface (the NT-1 is built-in)

We run a pair of Cisco 762's to hold up the ISDN between us and our
co-lo. Rock solid. Ascend ISDN routers stink (we had one for a while, it
wasn't very bulletproof)

sgd