[injuneer]

There used to a be a lot of phantom 999 calls after the parallel 112 code was introduced, a backward step really, a faulty line condition is more likely to dial 112 than 999, the answer was to set the line card circuit to receive MF (multi frequency) tones only at the switch (the default was loop disconnect/MF). I doubt many people have their phone set to use loop disconnect pulses anymore.