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- Jan 1, 1970
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We've discovered the hard way that the Voice Pro phone system needs a bit more loop current than what's being provided by the phone company. Our lines are clean but our local loop is about five miles, so the loop current is in the 18-19 milliamp range, which is a little below spec. The Voice Pro system objects to this condition by disconnecting callers at random or refusing to recognize certain of the CO lines. Hypothetically this is confirmed by temporarily eliminating the problem with the introduction of a nine volt battery in series with one of the troublesome lines. It's hypothetical because this experiment presumably violates FCC part 68 requirements or some other regulation.
So we're wrangling with the phone company over installing an extended range card that will put more power on our lines. But the question is what to do if they don't come through, or, more typically, take years to get it done (or go bankrupt in the mean time, since this is Qwest we're talking about). So does anyone have some hypothetical (or even legitmate) suggestions for working around this problem? A couple thoughts from someone without much specific knowledge of telephone electronics: 1) Switch a series power supply in only during an offhook condition. 2) Insert a negative-resistance op-amp circuit in series. Theoretically this should just cancel out some of the excess resistance in the long loop. Presumably an AC bypass would be needed to avoid having to deal with ring voltage.
Comments or links to circuits would be appreciated.
So we're wrangling with the phone company over installing an extended range card that will put more power on our lines. But the question is what to do if they don't come through, or, more typically, take years to get it done (or go bankrupt in the mean time, since this is Qwest we're talking about). So does anyone have some hypothetical (or even legitmate) suggestions for working around this problem? A couple thoughts from someone without much specific knowledge of telephone electronics: 1) Switch a series power supply in only during an offhook condition. 2) Insert a negative-resistance op-amp circuit in series. Theoretically this should just cancel out some of the excess resistance in the long loop. Presumably an AC bypass would be needed to avoid having to deal with ring voltage.
Comments or links to circuits would be appreciated.
