atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Smart Jack or not to Smart Jack?

When I refer to a smart jack, I am thinking of the "electrical interface" type of smart jack. Are they known by something else? The telco can send a loop up/down command to the termination point and test the line out.

Ok...why would the telco terminate on a 66 block over one of the devices I describe above?

The answers will lead me onto more questions but I'll use this as a starting point.

Regards,

Rick

The smart jack is typically a box on the wall with some lights and at least one circuit board visible behind a clear plastic cover, has at least one RJ45 jack, and a cable going to either the RJ21x block or other demarc. The smart jack converts the incoming 2 pair line to an RJ45 T1 or PRI line, you need a CSU/DSU between it and your equipment to handle the protocol translation. The smart jack and the cable going to it are the phone company's property and their responsibility to fix.

In a word lazy.

Many times here they will leave circuits on the outside of the building.

Often the SMARTJACKS for an office building are in the Main phone room/closet where all of the phone lines come in, and there is a "shelf" with many circuits (smartjacks)in it.
The individual smartjacks are extended to the particular office suite via the 25 pair feed cables to the 66 block in the office. Generally they are then hooked up to a special RJ48X jacks with shorting bars in them.

~Don~

A smart jack is nothing more than a jack with shorting bars that put a loop on the circuit when the modular cord is unplugged. The unit you are taking about, where telco sends out a 2713hz freq. to loop up to test the circuit is ahead of the smart jack. Some loop back devices do have a "smart jack" internally wired to keep the circuit "alive" if it's unplugged.

Sorry to complete your question if they bypass the loop back deivice the circuit couldn't be balances as all the gain and slope settings are in that loop back unit. Old ones were simply called 829's
Bill

[This message has been edited by justbill (edited January 31, 2005).]

Thanks for the answers. So in a perfect world, the telco would terminate on an 829 at the telco entry point for the facilty then extend the circuit to the modular jack w/shorting bars. Right? I've always refered to the 829's as Smart Jacks...incorrectly I guess.

Next Question:

When the telco terminates a T-1 in a facility, it has to have a certain amount of signal strenght, right? And is this signal strength measured in gain? And if the signal strength is a bit on the low side, can they increase the gain or adjust the LBO for that T-1? If so, where would they do the adjustment...at the 829?

Again...thanks in advance for your help!!

Smart jack is another abused term, It kind of' depends on who you talk with and you will get some different answers. The NIU (Network Interface Unit) is most often called the smart jack. The NIU is usually the Telco’s d-marc unless extended by them, usually on a 48x jack (shorting pins) or 48c jack (no shorting pins). The 48x is sometimes called a smart jack because of the shorting pins. The NIU is remote loopable from the C.O. There are many varieties of NIU's but all pretty much do the same thing. They provide demarcation; a testing point, protection, line status and some log a trouble history. T1 NIU's are looped with digital codes. The 2713Hz is for looping dedicated analog ckts. like 9.6 ckts. Etc....

WOW you guys got it made. If I get label I think its a good day. Jacks and everything huh?

SST is correct, was having a senior moment. The Network interface unit it where telco hands off a T-1, unless the sub pays for an extended DEMARC. Sorry about taking you down the wrong path. As SST stated the 829 type loop back units are for private line data type services. Your other question on levels is yes there are level requirements, but depends on how you get the T-1 as to what they are...and again this is a senior memory taking to ya. Fiber is 0 db and if I remember right copper is -8 db.

T1 Smart Jacks, AKA: T1 NIU's, depending on the LEC, perform more than just loopback continuity functions. The lates generation of T1-NIU's also contain Performance Monitoring, or PM, data. PM data is monitored in both direction of the T1 signal path. Typical PM data collected would be BPV, Loss Of Signal, excessive zero's (Line events), and Path Errors, such as CRC-6 for ESF, frame bit errors for SF frammed circuits. Timing slips are not typically tracked by NIU's. One other usefull function by most current Ti-NIU's is that it hasthe ability to notify the network (Telco CO) that the CPE has either been disconnected, of has failed at the input. When a T1 circuit losses framing into the NIU, and where the signal has degraded to the point where upstream MUX equipment invokes an unframed all ones (AIS), the T1-NIU will send a modified AIS known as AIS-CI. AIS-CI, and RAI-CI, CPE fault yellow alarm, have been in the ANSI standards since the late 90's. Typical CPE eight pin jack interfaces are configured as RJ48C. The 48X interface has been phased out by "most" Telco's since it would defeat the AIS-CI feature should the CPE disconnect from the network interface. One additional note. HDSL remote units have incorporated the very same, if not similar operational functions of T1-NIU's, to include in-band loop up/down support for FT1 circuits (Verizon Territory) using the DDS NEI/RPTR loop codes.

Hey Field ops, welcome. I remember those units and we could also access them remotely, if I remember right (see age related issues in this post) on remote testing you had to think backwards or what you saw in the PM data would mess with your head. Keep in mind these were very new at the time.

"CPE fault Yellow alarm" may be an ANSI standard from the late 90's but the bell system has had it from before 1970. The old D1B carrer system only had two signal alamrs red and amber(yellow). Red was when the system could not see a signal it could sync to. amber was a signal sent by a system with a red alarm to tell the other end that it could not see its signal.

I think a lot of the ANSI standards came from the old Bell system standards.

I have a T1 on an InterTel Axxess system that keeps dropping into red alarm, When I called in the tech said to look at the LED's on the smartjack. I show Power lit green and ESF lit green but flucuating.

Question is What is ESF? Should it be flucuating? and is this an indication of a problem with our provider.

Usually, if the ESF light is lit, then the T1 is configured for Extended Super Frame (ISDN-PRI). If it's not lit, it is configured differently or there is a problem with the circuit. I just checked ours here and it's lit steady. A few weeks ago, our circuit went out a few times and each time, the ESF light was flickering. My guess would be that you definitely have a problem with the circuit from your service provider.

Wow… You dug up an oldie but a goodie with this post!

ESF= Extended Super Frame
No, it should not be bouncing. You’re getting framing errors for some reason. That would be a Telco issue they need to resolve.

Excellent. Thanks for the help folks. I am by no means a newbie to this phone stuff, but I'm never sure whether to call our InterTel or Sprint. Finding these forums is the best thing I ever did!

Thanks again for your help.

Maybe getting a CSU that is "Smart" something like the Kentrox T-Smart would help as a test tool. It will let you see which way the errors are coming from you or the network.

Does a Smart Jack need to be plugged into local AC power or is power provided by telco?

If you are referring to a T1 termination card mounting, A.K.A: NIU, then the answer is probably no. Most stand-alone circuits are line powered these days.

It is generally better if you start your own new thread instead of tagging onto an old one. That way you will receive a response more promptly. This original thread dates back to 2005!

Ed -

When I worked for the Independent Carriers (AT&T, Nextlink, Winstar, ART, Teligent, Telergy etc.) ALL the smartjacks were locally powered. The only ones I ever saw that were line powered were the ones from Bell Atlantic.

Sam

Holly old posts Batman…

Like Ed said most NIU’s or NID’s (network interface devices) aka “smart jacks” are line powered.

Depends on the type of smartjack and the carrier...some are line powered, some are locally powered. Can't really say it'll be one way or the other. I've seen plenty of both.