The network has been modified several times through franchise reviews that have taken place in 1963, 1967, 1974, 1980 and 1991, during which broadcast regions have changed and service operators have been replaced.
Jaringan penyiaran ini telah dimodifikasi beberapa kali melalui ulasan waralaba yang telah terjadi pada tahun 1963 1967, 1974, 1980 dan 1991, dimana siaran daerah telah berubah dan operator layanan telah diganti.