Well, to be more clear, the difference between a "DS3" interface and a "T3"
interface is simply that the T3 is intended to be used outside the
building. For example, Cisco Systems here in Austin has a T3 line which
connects us to the backbone provider at the telephone CO, about a mile
away. Definitely an outside kind of thing. DS3, on the other hand, is
"cross-connect" type connection which runs only between racks in the same
building and does not require AC power fault and lightning testing.
T3 is indeed a TNV interface. DS3 is SELV.
Bellcore GR-1089 has tests for "broadband telecommunications interface" in
section 4.6, and this would be applicable for T3. These are pretty hairy
tests. There are different requirements depending on whether the equipment
is intended to be used with an external protector, whether it's outdoor
type equipment, etc.
T3 line protection circuit will involve a transformer, a fuse and a
gas-tube type surge protector. A "SidACTOR" type device has way too much
capacitance to operate on a T3. The Overvoltage and lightning tests (plus
all other TNV type tests) in UL 1950 are applicable if the flowchart does
not get you out of it (fire enclosure, 100A^2/sec limiting, etc.).
Good luck!
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Josh Karnes Lead Safety Engineer Cisco Systems - Austin
-------------------------------------------
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
To cancel your subscription, send mail to:
majord...@ieee.org
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Jim Bacher: jim_bac...@mail.monarch.com
Michael Garretson: pstc_ad...@garretson.org
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
