Just exactly how does a telephone work?

Question

One of my random questions again...........but exactly how does the physical "voice" travel over a wire?

Answer 1

ive always wondered this! ..interested to hear peoples answers on this one

Answer 2

At it's most basic:

When you speak into the hand piece, the vibrations from your voice cause an element in the microphone to vibrate in sync with your voice. These vibrations are changed to electrical impulses, also in sync with your voice.

The electrical impulses go down a pair of wires. At the other end of the wires is a speaker, which is a coil attached to a paper cone. The coil is an electromagnet. The electrical impulses going through the coil cause a steel slug in the coil and attached to the paper cone to vibrate in sync with the pulses, replicating your voice. The paper cone makes these tiny vibrations audible.

Answer 3

The phone system depends on current flow, not a set voltage level.  Your voice modulates the current flow and it's demodulated at the other end.  There's only 2 wires and the voices from both ends travel over these wires.  A hybrid separates the transmit and receive audio in each phone.  This is to prevent your own voice from being much louder than the voice of the person at the other end of the call.  

When you pick up your handset, the impedance seen by the central office changes.  It goes from a high impedance to a lower one.  This tells the equipment the phone is off the hook and it sends dial tone.  You dial the number you want.  It used to count pulses from the old dial phone.  Now it decodes the DTMF tones.  Either way, this tells the central office equipment which number you want to be connected to.  A connection is made and a ring voltage, about 70 to 90 volts AC at about 20 Hz, is sent down the line to the phone at the other end to cause the ring.  When it's picked up the change in impedance again tells the central office to remove the ring voltage and complete the connection between the 2 phones.  During the call, the phone impedance remains low.  When the call is finished, the impedance goes high on both lines and the CO equipment releases the lines and it's ready for the next call.

Answer 4

Hi bcantr,

You have heard about VOIP, but you have no idea what it is. Is this just another telephone carrier that has come along since the breakup of AT&T many years ago? Well, that is part of it, but this is another step further along as this system directly relies on the internet.

So, what is VOIP? It is Voice over Internet Protocol, a way of routing voice conversations using the internet or any other IP-based system as you continue using a regular telephone instrument. Okay, but how does it work? Can you be working on your computer and talk at the same time? Is there special equipment you need?

There are several companies that provide VOIP service. There is a cost savings because you have a single network to do everything-it carries both voice and data and on the same internet lines. If you have the right company that can carry both the voice and data lines together, there might be no additional cost to combine these two features.

The VOIP telephone system can help by automatically routing incoming telephone calls to your VOIP phone, regardless of whether or not you are connected to the network. You can take you phone with you on a trip and whenever you connect to the Internet you can accept incoming calls.

You can get free telephone numbers for use in some countries. People using this system can work anywhere as long as there is a sufficiently fast and stable Internet connection available to them. Like your other telephone system, you can usually get 3-way calling, call forwarding, automatic redial, and even caller ID.

So, is this system right for you? There are definitely advantages and as with all systems, some disadvantages. How do you choose? That depends and you should do some extensive research to make sure that the VOIP telephone system will work for you.

Well, you might actually be using a VOIP system at your office and not know it. The VOIP telephone systems have offered businesses high-powered telecommunications capabilities once available only to the largest, most expensive companies’ systems.

Today, advanced VOIP solutions enable all employees, whether they are down the hall or a thousand miles away, to respond rapidly to customers and business opportunities by allowing their phones and computers to integrate into one seamless system.

Check with your telecommunications people in your organization as they can tell you whether or not you are already using the system through work. They will also be very knowledgeable about the positive and negative components of the VOIP system and will probably be able and willing to talk to you extensively about their experiences with it. Remember, they are the people in your organization that must keep the computers and telephones up and operational for the company.

So, what do you think? Do you want to take the plunge and try the VOIP telephone system? Go ahead and take a chance if you think it will work for you. If it does not, you can always change back to a regular telephone.

Answer 5

what wires said... right on target.

must be a phoneman.