DuoFone 43-2638 (Radio Shack) telephone recording controller This device has a standard modular jack to plug into the telephone line. There is also a 1/8" (3.5mm) plug for either the microphone jack or the earphone jack of an old style cassette recorders. There is also a 1/16" plug that would have controlled the motor, but I have no use for that as I am simply interested in using the audio as an input to my mixer. I have been experimenting with attaching the tip/ring wires of the 1/8" jack to attempt to use this as an input either into a 1/4" line or XLR mic connector on a mixing board that I've had for awhile, but I am always getting an annoying hum no matter what pins I hook it up to. I've forgotten more electronics than I remember from 50 years ago in school and am wondering if anyone knows if I need to install a capacitor or a resistor either in series or parallel to make the buzzing go away and just sound normal. Before anyone "goes off" about wiretapping laws this would be used as likely the 2nd line for a podcast. I already have TRRS cable to go into my cell phone and have that portion working wonderfully. Any help will be greatly appreciated.