Two sets of parameters are defined by the International Telcommunications Union in ITU-R Recommendation BT.470 (see Appendix V) for analogue television services:
1 Colour encoding systems, falling into three main categories (see Table App.R.1)
2 Scanning and modulation parameters given single letter designations (see Table App.R.2).
These are added together to describe a particular service, e.g. PAL-I for the UK and SECAM-L for France. See also Appendix I.
Table App.R.1 Colour television encoding system parameters
Table App.R.2 World analogue television systems