that, when such recorded sound programmes are exchanged in the form of analogue magnetic recordings on tape, the exchanges should be effected by means of 6.3 mm wide tapes recorded at a speed of 38.1 cm/s or 19.05 cm/s,conforming with IEC Publication 94-1
ITU-R BR.407-4-1990 history
1990ITU-R BR.407-4-1990 International Exchange of Sound Programmes Recorded in Analogue Form - Section 10/11F - Exchange of Recorded Sound Programmes