Noise on paging system (CS1000, UXT

[rbelleroseanalog]

thread798-1698595

So my previous post indicated that our vendor hears noise on the overhead speakers off the paging amplifiers and the electrician with very little voice experience was trying to eliminate the noise with shunts and grounding the shielded cable that was being used. Fiber was suggested as an alternative to the the 900 foot run of copper that was used eventhough shielded and grounded with ferrites attached they inidcated they had noise on the wire itself and this was causing the noise on the overhead speakers.
They replaced the 900 foot copper run with mm fiber with transcievers and the noise was still heard over the overhead speakers with no paging activity.
I asked the electrician if he had put the amp and speaker directly on the trunk pair at the PBX and when he eventually did this he came to me and said the noise was comming from the trunk pair over his AMP and speaker. He asked me how I can eliminate the noise being heard? I confirmed the impedence match was set to 600 ohm to match the input. Funny thing when I use my butt set directly on the pair and test page I don't hear any noise on my butt set and the page works fine. I find it hard to believe that the paging trunk when on-hook is generating noise, I could understand if noise was being heard during the page but when the trunk is on hook and not being used they claim it causing the noise.
Am I crazy but the common item here is the amplifier and the speaker attached and I tend to think the Amplifier is the cause not the wire, fiber or the trunk port.
I am going to move the trunk port to another one on a different card and have them test again.
Anyone ever have this issue with white noise being heard on the overhead speakers with the paging trunk on hook?
My next step after that is to take the speaker they are using with no amp and see if the trunk port has enough power to drive the speaker like my but sett and see if I hear noise when I am not paging, on hook....


Sorry for the long post. Trunk RDB below...
Thanks for any input!


ROUT 11
TYPE RDB
CUST 00
ROUT 11
DES PAG1
TKTP PAG
NPID_TBL_NUM 0
NACC PGNR
ESN NO
VTRK NO
CNDP UKWN
ICOG OGT
SRCH LIN
STEP
ACOD 701
TARG 01 08
CLEN 1
OABS
TIMR ICF 512
OGF 512
EOD 13952
DSI 34944
NRD 10112
DDL 70
ODT 4096
RGV 640
GRD 896
SFB 3
IENB 5
TFD 30
SST 5 0
NEDC ETH
FEDC ETH
HOLD 02 02 40
SEIZ 02 02
RGFL 02 02
CDR NO
MUS NO
TTBL 0
OHTD NO
ALRM NO
ART 0
SGRP 0
ARDN NO
CTBL 0
AACR NO


Tnb
DES pag1
TN 004 1 00 07
TYPE PAG
CUST 0
XTRK XUT
TIMP 600
BIMP 3COM
RTMB 11 1
SIGL
STRO IMM
AST NO
IAPG 0
CLS UNR DIP CND ECD WTA LPR THFD SPCD
P10 VNL
AACR NO

 

[KCFLHRC]

I would install a WMT-1 Line matching transformer, goes between the page trunk and the amp.

 

[MikeInHouston]

You also may have a floating ground issue. Make sure that the PBX is properly grounded as well.

Mike