Distance problem on 2616/3904 sets?

[bad69cat]

Hi guys,

I have been battling an intermittent problem for quite awhile with phones that seem to die, or act up when booting up..... sometimes I can get them to come up and other times I can't. Sometimes a 3904 will run on a line when a 2616 won't on the same line? It's a pretty long run from the OPT81 to the building where this is happening. Not sure on the distance but I bet it's at least 1500 ft. maybe more....
I imagine it's right on the edge of to far. Is there a way to boost the signal on a TN port basis? Or maybe on a whole card even? I'm at a loss as to what I can do....?

 

[Firebird Scrambler]

I have this two old reports below

ANALOGUE EXTN LINE LIMITS / DIGITAL LOOP RESISTANCE.

For 500 set:
REN 1/2...........MAX LOOP RESISTANCE......1000 OHMS
REN 3.............MAX LOOP RESISTANCE...... 900 OHMS
REN 4..............MAX LOOP RESISTANCE...... 600 OHMS
REN 5..............MAX LOOP REISTANCE......... 350 OHMS

For 500 set:
ASSUMING YOU ARE USING 0.5MM COPPER CABLE THE
FOLLOWING IS A GUIDE TO THE MAXIMUM LENGTH OF
CABLE TO BE USED:-

REN 1/2..............11.4 KILOMETRES

REN 3.................10.25 KILOMETRES

REN 4.................6.8 KILOMETRES

REN 5.................4 KILOMETRES

PLEASE NOTE :: THESE FIGURES ARE FOR THE LINE LOOP
SO FOR EXAMPLE,AN EXTN WITH A REN OF 5 SHOULD NOT
BE FITTED MORE THAN 2 KILOMETRES FROM THE EQUIPT.

R = p.l/a

where R = resistance
p = resistivity ( copper is 17.2 x 10 to the power -9 )
l = length in metres
a = cross sectional area of the conducter ( metre sq )

For Aries type set:
Digital set loop resistance must be below 175 ohms. (approx 3000 ft)

############################

DIGITAL SETS ON NT8D02 I/F 1000m MAX.

############################



Firebird Scrambler

Nortel & Avaya Meridian 1 / Succession & BCM / Norstar Programmer

Website =

http://somertel.com

linkedin

 

[KCFLHRC]

About 3000 feet or so on a digital set with 24 gauge wire

 

[bad69cat]

OK - well... I dont think it s that far then...>?

 

[KCFLHRC]

Could be a bad line card. One thing to keep in mind also is the 2616 is polarity sensitive where the 3904 is not.

 

[bad69cat]

Yeah the polarity is correct Im pretty sure. I guess I could try swapping the line card out...... there is no data change I could make that would cahnge the output though? Maybe I'm thinking of the Avaya or Siemens switch....?

 

[KCFLHRC]

There could just be a weak component on the card, worth a shot. No data change that will boost the signal though. Is this on all inside wire or does it leave the building and go outside?

 

[bad69cat]

It leaves the PBX and goes outside about 1200 to 2000 ft at most I think to another building. Not sure of the guage, but it's a burried type cable.... so I assume 24 or 22?

 

[KCFLHRC]

Typically buried cable is minimum 22 gauge. Hopefully it has lightning protection on it. The gas or carbon modules would be something to look at if it is in fact protected which it should be.

 

[PERRYPJ]

If you were not there when the cable was placed in the ground you have no idea where it goes, I would not rule out bridge tap

OLD ROLMEN WORKING ON NORTELS AND AVAYA

 

[bad69cat]

Yeah - I did a little more troublshooting this morning quick. It's kind a goofy setup. It's a 2 story building and apparently they remodled it at sme point. I think they cobbled a few thigns together.... the 1st floor must have been orginal entry point and then they decided to extend the Dmarc to upstairs and have the patch pannels there. The phones I'm having troubles with have sidecars, and I noticed that I can run a phone without a sidecar. SO it's definately a level loss. I cannot figure out where they tied the staion ports to the Dmarc cross conn's..? I have a feeling they have yet another connection point under the raised floors somewhere....? I get tone on ports that are not cross connected at the patch pannels..... so yeah, it's bridged somewhere and I can't find it. IT's been working for years though, so somehting has changed..... I may end up running my own station ports directly downstairs to the original Dmarc if I get deperate, but that is going to be a real PITA - which is why it wasn't done in the first place I would bet. I amy try swapping out that line card if I can get in after hours and hope that fixes it. I have my doubts.....