Private Telecommunication Network (PTN);Inter-exchange signalling protocol;Do not disturb and do not disturb override supplementary services (Endorsed by Asociación Española de Normalización in July of 2022.)
Private Telecommunication Network (PTN);Inter-exchange signalling protocol;Do not disturb and do not disturb override supplementary services (Endorsed by Asociación Española de Normalización in July of 2022.)
