This part of IEC 834 applies to narrowband and wideband teleprotection systems used to convey analogue information about the primary quantities such as phase or phase and amplitude. The teleprotection equipment can either be separate or integrated in one unit with the protection equipment or the telecommunication equipment. Narrow-band systems include systems operating within a 4 kHz band (for each direction of transmission). Wide-band systems include systems occupying more than 4 kHz bandwidth (for each direction of transmission). Broad-band command systems are not dealt with in this standard.