Phone Line to Audio · CircuitsArchive

01 Mar 1998

This circuit uses an audio coupling transformer and a capacitor.

The primary windings add in series to 500 ohms. Instead of connecting them directly together, add a cap between them. It was something like 0.047 micro farads with a 600V rating. And the secondary which is 500 ohms runs into the control room mixer.

                Tip   >------------/ II 
                                   / II /-------< 
           (primary winding 1)     / II / 
                                   / II / 
                      >-----X------/ II / 
                            I        II / 
              0.047 uF      =        II / -----CT   (secondary winding) 
                            I        II / 
                     >------X------/ II /          Output Side to Mixer 
                                   / II /                         
           (primary winding 2)     / II / 
                                   / II /-------< 
             Ring    >-------------/ II 
``

Sources
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-   tpappas\[at\]hamp.hampshire.edu

[Category:Telephone](/circuits/telephone)