VOIP lines distorted

[pilasz]

IP office 500v2
VOIP lines supplied by Cablevision.

This happened at two locations.
Voice sounds distorted (sort of like you have too high signal on the input and equipment cannot handle it).
Placed several service calls - result - as expected.
Anyone had similar issues?
With butt-set it does not sound as bad, but it is still there.
Locations are in two different states, but provider is the same.
Any help would be appreciated.

 

[mforrence]

If you can test with butt-set, they must be handing off to you as analog. Have you done impedance matching? What is off-hook current? Target is generally 25ma, with anything above 35ma causing grief.

 

[pilasz]

Yes, they provide me analog lines. Not sure how to measure off-hook current (same as any other - in-line amp meter?)
Impedance matching?
Know what it is in general electronics (or audio) but not sure how it applies here.
Generally low impedance source goes to hi impedance input. Is it different here? Do I need or should I try something?
Please let me know. At this point I will try anything.

 

[amriddle01]

You need to te them to supply equipment and/or lines that do not have noise on them

 

[mforrence]

1. Off-hook current is measured with a meter - generally any multimeter will do. Built into many test sets.
2. Impedance matching is a testing function within IP Office Manager
3. Low impedance source to high impedance input is good with sound systems. In telephony, it is best if they match.
4. If you have the noise on your butt set, you'll have it on the phone system.

 

[pilasz]

Thanks. Will measure and let you know.

 

[pilasz]

Remotely connected to the system.
Impedance (measured) shows 600+2150nF - looks good.
Hovever the GAINS section shows blank fields.
Any other system - odB.
Since both system used same basic template - that may be the issue.
Will set gain to 0dB and see if that helps.
Still puzzled why lines sound slightly distorted on the But-set.
On the other hand never paid any attention to this type of thing before - maybe my butt-set is not really good.
J.

 

[amriddle01]

May be worth checking if they can provide SIP direct rather than via modem, will sound better and give more features (twinning, call control etc)

 

[pilasz]

Unfortunately newbie as far as SIP lines go. Any tips who is good provider for those?
Have several clients using Cablevision lines, and be more than happy to switch.

 

[pilasz]

Somewhere during upgrade db level for lines went to (null). Most likely it was boosting lines to maximum. After resetting it to 0 - all problems went away.
Thanks all for the help.