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Subject: Telephone Isolation from power ground
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Date: 03/12/02 at 12:40 AM
Posted by: Majed
I'm designing a telephone circuit using Motorolla's MC34010 telephone chip. I'm feeding the telephone circuit from the telephone line through a bridge rectifier.Although, I'm using 5vdc linear power supply to feed other parts of the design. The linear power supply separates the power ground from the telephone ground.
the problem comes when I connect the DP9 connector of my telephone to the PC for some data transfer operations. Since the PC use the main power ground as a refrence it'll not allow my design to work. Since the tip & ring of the line are actually refrenced to the power ground.
Please I need a quick help if there's an easy and efficient way to isolate the tip & ring from the power ground as a refrence. Any suggestion will be appreciated.
I can provide the circuit if needed.
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