Hi Folks: I have a question about the interface circuit for the new SDSL standard ETSI TS 101 524. The interface I am interested in is the LTU interface that goes in the central office. There is an option for this interface to provide a small wetting current of about 5 mA to overcome corroded connections in the loop. I am trying to figure out how to provide the wetting current.
Is it feasible to simply apply -48 volts and ground through a pair of matched 4,000 ohm resistors? Is there any reason why this modest impedance to ground (balanced, of course) would cause a problem? What is the standard practice for sourcing wetting current in an SDSL circuit? Any advice would be much appreciated. Joe Randolph
