Hello
could you tell me how phone line transfer and receive our voice?
as you know when we answer the phone the voltage of phone line decrease to 8volt.i make this experience(Make to phone Parallel)
in the left circuit when i speack to one of the telephone i can hear my sound very good.but in right circuit i hear my sound difficulty.why?what is difference between my battery voltage and phone line voltage?
The power supply on the right side is a low impedance path, so it short circuits the analog voice signal.
If you change that for, say, a 48Vdc supply WITH a SERIES 1kohm resistor (a high impedance for the matters) it will do the trick.