Page 50 - eBOOK FUNDAMENTAL OF TELECOMMUNICATION NETWORK
P. 50

The local exchange will supply DC voltage; -48 Volt to the

                 Customer Premise Equipment (CPE).




                 Once  user  pick-up  the  phone  (off-hook),  the  circuit

                 between  the  telephone  device  and  local  exchange  will

                 change to the closed circuit.




                 Then,  the  voltage  and  current  from  local  exchange  will

                 flows over it. (Direct Current)





































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