It is used to identify members of the same force and to detect any enemy infiltration on a voice circuit. Codes are given out according to a card. All friendly forces will have this card and will ask a station on joining the net to answer a question with regards to this card.
Kusetyenziselwa ukwalatha amalungu omkhosi kunye nokufumana ungenelelo lwalo naluphina utshaba kwisekethi yelwizwi. Ikhowudi zinikezelwa ngokwekhadi. Yonke imikhosi engabahlobo iza kubanalo eli khadi ize ifune isitishi esidibanayo kwinethi ukuba siphendule ngokubhekiselele kweli khadi.