Examples of region coding and system:

Region 0: worldwide
System: NTSC

Region 0: worldwide
System: NTSC

Region 5: (the rest of Africa, former Soviet Union, the Indian subcontinent, Mongolia, North Korea)
System: PAL

Region 4: (Australasia, Central America, the Caribbean, Mexico, Oceania, South America)
System: unknown 

Region 4: (Australasia, Central America, the Caribbean, Mexico, Oceania, South America)
System: unknown 

Region 2: (The Middle East, Western Europe, Central Europe, Egypt, French overseas territories, Greenland, Japan, Lesotho, South Africa and Swaziland)
System: NTSC

Regions 1-6:
System: PAL