Busy out POTS line

Or bankrupt the telco with a huge power bill! (I don't know what to do on that one, because both my telco and my electric company are cooperatives, so I'm a "stockholder" in both...)

Probably send you to Gitmo to get more information out of the "informants", given that tortured logic! ;-)

Just think... if *thousands* of them are offhook, this will melt the pavement in places where buried cable crosses a street.

Don't mention "Craig", or somebody will start it up again.

None of the above is correct.

The best resistance value is 0 ohms.

The /impedance/ of the circuit is 600 (or 900) ohms, and that has absolutely *nothing* to do with loop current or hookswitch supervision.

The exact specification for the maximum resistance still guaranteed to cause an offhook varies from country to country, as does loop current. The North American Standard and the ITU/CCITT standard are the same, but several countries have their own standards (usually for lower loop current to allow longer loops).

Typically the North American (Bell) standard for loop current is a 20 mA decision point with a minimum of 23 mA required for operation, and allows for a 400 Ohm resistance in the line card (line relay resistance). Additional resistance (or current limiting) can be used, and the absolute maximum loop current allowed is 120 mA while the maximum recommended is 60 mA. Typical switching systems use anything from 27-60, but 35-45 is most common.

The effect is simple. With a minimum of 23 mA required, and 400 Ohms in the line card, the rest of the necessary resistance is split between the cable loop and the resistance of the telephone set. The specified "maximum resistance guaranteed to cause an offhook" is the maximum resistance a telephone set can have if it is attached to the longest cable loop that the telco is allowed to install.

That is perfect, regardless of distance from the CO.

I once discovered that I could put a NE-51 neon light (just the light, no resistor) across the phone line and an interesting thing happens. When the Co rings the phone, the neon light gets 90 or so volts AC, and that causes the neon light to flash and in so doing, it becomes a short circuit to the ringer current for that part of a cycle. But since it's drawing current, the CO thinks the phone has gone off hook. So it interprets that as an answer. But then the voltage drops down to 48VDC, which is not enough to keep the neon light on, so it extinguishes. And then of course the CO thinks your 'phone' has hung up so it's back to as if the phone is on hook. And that allows you to make an outgoing call. If you have a phone also on the line, you might hear a slight tinkle of the ringer, but not much.

The other end doesn't hear a busy, just part of a ring, and then nothing as if the called phone on the other end had hung up. Finally after a time the CO will give an error message. This seems like an excellent way to discourage telemarketers from calling, since they can't complete a call, but get weirdness instead.

And then the phone police show up because someone reported Ring-Trip trouble on the line.

Now for fun, you could call forward the line to a intercepted number. Our Happy Loser Telco still has one of my old numbers on disconnect notice and that makes a neat parlor trick :-)

Carl Navarro