Combined operation of 24-channel cable carrier and 12-channel open-wire carrier systems

COMBINED operation of two carrier systems working at different frequencies and on different types of facilities, through frequency-translating equipment, has been used for some time. Combined operation of K-J systems was introduced in the mid-thirties. This system makes use of the 12-channel twin-cable K carrier operating in the frequency range of 12 to 60 kc, and the 12-channel open-wire J system operating in the frequency range of 36 to 144 kc. More recently, 0-N combined operation over cable and open wire has become available. The 0-N system is a 20-channel single-cable carrier translated into 4-channel open-wire groups in the 0-frequency range. The frequency range of the 20-channel 0-N in the cable portion is 40 to 264 kc. That of the open-wire portion extends up to 156 kc. depending upon the frequencies selected for the open-wire section. The 0 system does not co-ordinate in level and frequency with J.