[Asterisk-Users] TDM400P Revision question.

[Eric Wieling]

Rich Adamson wrote:

>>My specific issue has to do with ringing on my FXS ports.
>>
>>A Northen Telecom Harmony phone (circa 1983) rings normally but when I connect my newer GE 
> 
> 2.4GHz cordless I never get more than 1/2 ring (it lights up and works fine... just can't get a 
> ring from it). Normally I'd assume that it's a low power issue on the FXS port but with a phone 
> rated at 0.1 REM?
> 
>>I do have some strange voltages though....
>>
>>ON-Hook: ~48V DC, 107V AC (this really concerns me...)
>>Off-hook: ~6V DC, ~12VAC (where the hell is this AC component coming from???)
>>Ring: 0V DC, ~45V AC
>>
>>Suffice it to say that electrically this is completely out to lunch... I'd like to throw an 
> 
> oscilloscope on the line to see what's what but I'm having trouble finding one.
> 
> 
> That on-hook AC is a real problem "if" the voltmeter is accuate.
> 
> Couple of things to try....
> 
> 1. Go to the demarc, disconnect the in-house wiring and measure the AC
> component again (only looking towards the telco's CO).
> 
> 2. Disconnect asterisk and install an ordinary analog phone. Take
> the phone off-hook and measure the AC. If the value is very small,
> then the voltmeter is measuring induced AC on the "unterminated"
> wiring. (The phone being off-hook creates the termination.)
> 
> Put the phone on-hook and measure again. If the value is large, then
> go looking for the source of the induced AC. Things like wall-warts,
> fluorescent light ballasts, any device with a transformer in it,
> electric motors (of some fairly large size), desktop high intensity
> lamps (with internal transformer), etc, can cause inducedAC "if" 
> they are within inches of the wiring.
> 
> Using a scope would be good, but it will only validate the voltmeter
> results; nothing more. If you're unsure about the quality of the
> voltmeter, borrow another one from someone and compare the results.

Doesn't anyone use Google anymore?

http://lists.digium.com/pipermail/asterisk-users/2005-April/098934.html

Also:

http://www.google.com/search?hl=en&q=site%3Alists.digium.com+boostringer&btnG=Google+Search



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