Video : From (4/3)TV to DV

Television in Australia : PAL : 625 lines at 25 fps

NTSC (USA, Canada, Japan) 525 line, 30 fps

Secam : in France and other countries that wanted to be imcompatible with the rest of the world :-)

Albania, Benin, Bulgaria, Congo, former Czechoslovakia, Djibouti, Egypt, France, French Guiana, Gabon, Greece (also PAL), Guadeloupe, Haiti, Hungary, Iran, Iraq, Ivory Coast, Lebanon, Libya, Luxembourg (also PAL), Madagascar, Martinique, Mauritius, Monaco (also PAL), Mongolia, Morocco, New Caledonia, Niger, Poland, Reunion, Romania, Saudi Arabia (also PAL), Senegal, Syria, Tahiti, Togo, Tunisia, the former USSR, Viet Nam, & Zaire.

PAL :  (Phase Alternation by Line)

Line Frequency 15.625 kHz (1/((1/25)/625))

PAL countries include: Afghanistan, Algeria, Argentina (PAL-N), Australia, Austria, Bahrain, Bangladesh, Belgium, Brunei, Cameroon, Canary Islands, China, Cyprus, Denmark, Finland, Germany, Ghana, Gibraltar, Greece (also Secam), Hong Kong, Iceland, India, Indonesia, Ireland, Israel, Italy, Jordan, Kenya, North Korea, Kuwait, Liberia, Luxembourg (also Secam), Madeira, New Zealand, Nigeria, Norway, Oman, Pakistan, Paraguay (PAL-N), Portugal, Qatar, Saudi Arabia (also Secam), Sierra Leone, Singapore, South Africa, Spain, Sri Lanka, Sudan, Swaziland, Tanzania, Thailand, Turkey, Uganda, United Arab Emirates, United Kingdom, Uruguay (PAL-N), Yemen (the former Yemen Arab Republic was PAL, and the former People's Democratic Republic of Yemen was NTSC, Yugoslavia, Zambia, Zimbabwe.

Brazil wanted to be really different and uses PAL-M which is essentially to PAL at NTSC line and frame rates.

The signal sent is analog

Continuous stream of data

For more about Pal/Secam vs NTSC : http://www.videointerchange.com/pal_secam_conversions.htm