[geeks] News server access

[John Duksta]

Please allow me to straighten out some of the misinformation
being given here about DSL, ISDN and T1 local loops.
These specifications are what the telco is going to
give you for your demarc for each technology. Distance limitations
always refer to the distance from your CO to your demarc.

T1 - 4 wire balanced (separate pairs for transmit and receive)
basically unlimited local loop distance from CO (with repeaters)
Usually uses B8ZS for line encoding

ISDN - 2 Wire conditioned line (may not have any load loops in the
line.) You do however get a 4 wire interface off of your NT-1, but that's
not your demarc. Usual limit for local loop is 18,000 feet (wire length)
from CO. Anything more than that requires the use of repeaters. Repeaters
can also be used to boost signal strength on poor quality lines at
shorter distances (but is not recommended.) Standard encoding is 2B1Q.

ADSL - 2 Wire conditioned line (like ISDN). Also has 18K feet
limitation. Designed not to be used with repeaters. Line encoding is
usually DMT.

-john



--
John Duksta           | "No! You can't take my Focusyn! I need every brain
Security Engineer     |  cell blazing to outwit my invisible enemies."
Genuity               | - Bart Simpson