Originally posted by justbill:
IMHO unless he's right on top the CO or feed by carrier that's misaligned levels are not going to be an issue. I'd bet loop current isn't the issue either. I'm sticking with the problem lies with-in the IP system. Of course we won't know any of this for sure until we see the test results.
How can these IP developed systems all at once say the established requirements don't apply to us? At least that's the way I'm reading what mgere is telling us that he's being told by the IP systems tech support.
I’m still thinking you IMHO is correct, sir.
Disregarding long standing requirements and standards for equipment is happening on this side of the demarc too I’m afraid. It seems to be the way of the world when the CG’s and marketing people are driving the proverbial bus.
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I don’t know that this will specifically help the OP but typed this out for anyone else that happens to look here due to having similar issues and would like a little deeper discussion.
The DC component (loop current) found on telephone lines and the AC signal (voice) when present, is superimposed but the two elements are wholly separate. If you don’t believe me? … Place a call... Mute both ends so neither are transmitting or receiving any signal. Is the DC still flowing? Yup, sure enough is, the talk battery is still there.
On a POTS line, since the DC component is required to there to keep the line open at the switch, as well as power the transmitter and receiver of a telset, you can’t really “prove†that AC signals can exist without the DC on a regular POTS line… But there are a few examples of “special service circuits,†provided by telcos, that have no DC component but pass only AC signal over copper wires. Pretty much a thing of the past, but once upon a time it was done (i.e. old school analog data, hoot-n-hollar/junkyard lines, etc.) … And, I’ll leave the inherent corrosion issues on splice and sealing-current open to discuss for a different time, since this is already getting off track.
So, why is there even a conversation here (and in other posts) that seeming mixing and matching concerns with “loop current†and “signal?†... It’s the nature of how the telco plant is constructed. The DC current reading can be VERY telling since a voice line is an “electrical circuit†wherein the conductors make a majority of the load and the battery is a fixed value…. That Ohm was a smart feller, right.
When questions of “too hot of a signal†come up, the follow-up question is often what’s the “loop current†at the demarc.... Why if they are separate things? A person can make some very accurate assumptions about “the loop†the particular voice service is being delivered on... Or how “the loop†was conditioned for service delivery.
If the signal is “too hot†and the DC current is high, one of two likely conditions is present… And both are telco issues. 1) The loop is very short and the equipment on the other end was installed at default settings that are designed for more average (longer) loops and needs to be padded down. 2) The loops is very long and the telco over compensated when conditioning for the higher resistance and “loop loss†of the extra cable.
