Telephones aren't quite like that
Land lines are actually sampled 8000 times a second, in a perfect world that would mean your freq range would be up to 4000hz, in reality it works out to more like 3600, at the low end it is cut off below 30hz, for one thing the "ring" signal that is sent down a typical land line (i.e. not voip) is a 20hz @ 90 volts and they don't want that to be "audible" so there are filters that basically clamp you between 30hz and 3600hz. Of course for VoIP or cell phones it is a lot different, in land lines that single conversation eats up 64kbs of bandwidth, so they use various packet and compression technologies (g.711 - great, g.729 - good, g.723 - horrible) to pack more conversations in the same bandwidth. The more you compress, the worse the voice quality but the cheaper it is to transport. The fidelity goes in the toilet, hence the reason 99% of voip and cell phone calls don't actually use touch tones, they are for your benefit, they use out of band signaling - essentially a data-channel that says user pressed this button, user pressed that button, and if required it is converted to a tone at the other end. Even call progress signals (dial tone, busy tone, and so on) are generated inside your phone to save the precious bandwidth of sending a tone's worth of data over the network. This is also why you have the latency or delay when you talk on your voip or cell phone, call a friend's cell phone standing next to you with your cell phone and listen how long the delay is between him saying hello and you hearing hello. In any metro area the odds of that call traveling more than 2 miles is remote and a 2 mile connection would not have any perceivable delay, the delay is caused by the packet sample, then compress, then send, the receive, then decompress. then play... all on low power CPUs.
Sorry to anyone whom I have put to sleep, I just love tech discussions, love creating tech, and in fact find the technical aspects of Disney and WDI to be one of the most enchanting elements, wish I could work for them one day.
