A control circuit is a telephone-type circuit between the point of origin of the programme and the point where it terminates (recording equipment, studio, switching centre, transmitter, etc.) used by a broadcasting organization for the supervision and coordination of a sound or television transmission.
ITU-T N.3 FRENCH-1988 Referenced Document
ITU-T D.180 Occasional provision of circuits for international sound- and television-programme transmissions Series D: General Tariff Principles; General tariff principles - International sound-and television-programme transmissions Study Group 3*， 2005-09-01 Update