On Fri, 23 Jul 2004, Christopher Woodfield wrote:
OK, from my reading in Newton's Telecom Dictionary, it appears that NIU is a generic term for "whatever the customer plugs their cable into", be it a powered or a dumb device. Mea culpa. ... "...installed on the premises as a semi-intelligent demarcation point, the smart jack is completely passive until activated remotely by a digital code, typically something like 'FACILITY 2', sent down the T-1. This code activates a relay [that loops the circuit]."
That may not accurately define the Adtran and Westell devices that are pictured (they appear to have additional features beyond this), but it's a good guess they provide the remote loopback function described above in addition to the monitor points and management console port. I also doubt that the Hyperedge unit pictured does so, although I can't seem to find any online documentation on the unit (it is, as you described it, a 'glorified patch panel'). Feel free to correct me.
In Qwest land, NIU, Smart Jack, and Demarc (unless "extended") are all in the same physical rack. When you get a T1, qwest installs an appropriately sized shelf. This shelf holds the adtran and westell devices shown in earlier posts. For example, we have one site with quite a few T1's, which they installed a rack like the one pictured at: http://www.westell.com/images/osp/dsawm214.jpg Note the RJ45's on the bottom. These are the demarc point for the circuit. Older ones have RJ45's on the right side and the cards are thicker - a lot thicker. When qwest says "insert a loopback plug at the smartjack" or "unplug from the smartjack" or whatever, they mean this device. Qwest can loop or unloop and do other tests to this device. On the newer HDSL cards, they can also plug a laptop in to get performance data, and I believe they can also get this data from the CO end. Also of note, I haven't seen qwest deploy anything but HDSL2 cards for quite a while. This basically means a full duplex, full-speed T1 over a single pair of copper with a quarter of the repeaters (12K wire feet without a repeater). -forrest