How can a telephone work in a power outtage?

Question

Why is it that when the power is out, I can still make a phone call from my house on a phone with a cord?

Answer 1

Corded telephones, that do not use AC line power from your AC outlets, get their power over the telephone line, directly from the telephone company.  There is approximately -48 VDC on the telephone line that provides just enough power to enable a corded telephone to operate independently.

Answer 2

Telphones are powered by the phone company over their own lines.  They use DC current (35vdc) powered by backup generators and batteries at your local telephone company wire center.  The large farms of DC batteries they use can run for a considerable period of time without much or no AC (110vac house current) to recharge them.

This is how Alexander Grahm Bell designed the system in 1876 and this is how it functions today.

Answer 3

The telephone company provides the power on your landline phone, it do not connect on your main power supply at home just like any appliances.  You can measure the voltage reading by measuring from the wires of telephone lines.  It doesn't consume much unless a call is made or received.  I think more or less than 46 volts.

Answer 4

b/c those phones dont need power...

Answer 5

There are seperate lines for power and phone.

Where I live the power is supplied by Progress Energy and they have their own lines for the transmission of the the power throughout the area, while my local phone company uses their own lines for the phone service. You may not see the other lines because one set might be underground, but they are there.

Each line the company uses has a different use, for exmple the power cannot run through the phone line because the amount of power running through would destroy the phone lines - it's just too much power. Each company uses a line that is appropriate for the job needed.

Answer 6

because the phone grid and power grid are separate. Ever notice how you don't need to plug your phone into an outlet unless it's cordless?