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OPX Lines, low volume

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marcshunk

Technical User
Aug 13, 2003
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I have a couple dozen OPX lines that travel through the switch and then several miles over leased copper to another facility. The trouble is that I have too much Db loss on the OPX lines to make long distance calls easy to hear. The Db loss is fairly even on all the OPX lines, and there is normally some Db loss on a long distance call anyway. We have "cured" the low volume problem on the OPX lines for those who have complained by giving them amplified handsets. Is there any other way to boost the volume on the OPX lines? (say... a setting in one of the LDs of the switch?) Is there any type of bidirectional amplifier I can punch down in place of a bridging clip or the like? I'm looking for cheap (like not getting a "T" line or anything drastic like that).
 
On the OPS Line card (NT1R20) make sure that you have it configured as OPX,TIMP = 600, BIMP = 3COM2, Jumpers Jx.0 and Jx.1 (x = tn on card 0-7)are set to on. If this does not cure it then set up a new DDB (LD 57) for your long distance spans and adjust the DB levels there. Good Luck
 
Hi marcshunk,

First of all since the pairs are leased as ckts from a telco or service provider, you need to get them to redesign the loops with voice repeaters on each one with no more than -3.0dB loss end-to-end. I would start by opening trouble tickets with repair service and escalate from there. Over the years this has always been a problem with off-prem stations on copper. The losses are additive so you want to make sure your trunks have good levels also. Whenever I ordered OPS ckts from the telco, I always specified a -3.0dB loss design - NO EXCEPTIONS - Since you mentioned levels I assume you have test equipment to do measurements. But with only one TIMMS that could limit you somewhat.

You have another option here and that is to move all the off-prem stations to a point-to-point T1 ckt. I believe Northern Telecom makes a T1 station card for the M1 switches. I know they make one for trunks! (Why they did not just use one card for both I have never figured out.) On the station end you would use a channel bank with FXS cards and on the switch end use the T1 card. There are some nice channel bank packages available. One that comes to mind is the Carrier Access ADIT600 which has lots of flexibility and can support 2-T1s for a total of 48 channels and is very small.

Now obviously there are costs involved with this. Not knowing what your situation is, changing to a T1 could save you or your customer money and provide more options if you needed to haul data to/from the same location. Plus you are in control of the levels at this point and can taylor the design as needed.

Hope this helps!
JIM
 
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