The compandor should first be tested in accordance with the appropriate design information which should be made available in a suitable form to repeater station staff. In particular,because the unaffected level of a compandor is defined with reference to an 800 Hz signal,it should be verified for each type of compandor that use of a reference test frequency of 1020 Hz produces the same results as using a reference test frequency of 800 Hz.
ITU-T M.590-1988 history
1988ITU-T M.590-1988 SETTING UP AND LINING UP A CIRCUIT FITTED WITH A COMPANDOR