Low Volume on 8 Port Analog Trunk MBM

[bdalida]

I have a nasty situation. I have an end user with a BCM 200 3.7 with an 8 Port Analog Trunk MBM. I replaced this card as there were low volume issues. The replacement card worked for about 2 weeks and the same issue came up. I replaced the card again and 2 weeks later, the same
issue. They have 5 trunks and are getting low volume on 4 of the 5. I figured it was a bad BCM so I replaced the entire unit. Now after 3 weeks, I have the same issue. The system is on a UPS and the trunks have protection on them. We have had the local carrier out a couple times. When they test the trunks on site, they are fine. Have you seen this before? I am not sure what direction to go!!!!

 

[senk1s]

Country switch settings?

 

[bdalida]

Thanks, I'll look into that.

 

[MagnaRGP]

Have you tried increasing the loss package settings?

 

[bdalida]

No I haven't

 

[teekow]

Bulletin# 2006006589 references extreme ring current conditions that cause low volume on analog MBMs in a BCM50. The same MBMs are used among BCM50 and BCM200/400 so I would assume the same situation could exist. The fix is to work with tech support and level 2 at nortel was providing special switch tails that include 200 ohm resistors to protect the MBM ports. The setting at the CO is "ring trip current" which is different than "ring current" and evidently cannot be tested without special equipment.

Hope this helps
Rob

 

[JasonPM]

teekow,

That bulletin is specific to the four analog ports built into the BCM50, not the analog MBM's.

bdalida,

Have you verified with a butt set that the CO is good? Make sure to disconnect the BCM from the CO when you connect the butt set to isolate the line from the system.

J

 

[bdalida]

Phone company has been to site and tested all the trunks. They all check out. This is a strange one. BCM 400 has been replaced because of this problem and the MBM's have been replaced three times also. When a new MBM goes in, the trunks work great for about a month, then start to fade in volume.

 

[DigitelD]

It sounds like there is an incompatability some where between the BCM and telco.

 

[teekow]

FYI, bulletin # 2006006589 does not only refer to the main lines 61-64. The bulletin that references these lines is # 2005006242. Both bulletins deal with the same symptom of low volume. Bulletin 589 speaks to excess ring trip current, while bulletin 242 speaks to the need for patch 39. I suggest getting the special switch tail or installing 200 ohm, 2 watt resistors on both the tip and ring of each trunk. One of those scenarios should be in place prior to installing another replacement MBM.

Hope this helps
Rob