Ros Hásáná / sófárfújások

The order of the blasts is three sets of three blasts each, which are: Tekia, terua, and tekia. The length of a tekia is equal to the length of three teruot, and the length of a terua is equal to the length of three whimpers. If one sounded the firsttekia of the initial series of tekia, terua, tekia, and then extended the secondtekia of that series to the length of twotekiot, so that it should count as both the second tekia of the first set and the first tekia of the second set, he has in his hand the fulfillment of only onetekia, and he must begin the second set with a new tekia. With regard to one who recited the blessings of the additional prayer, and only afterward a shofar became available to him, he sounds a tekia, sounds a terua, and sounds a tekia, an order he repeats three times.Just as the prayer leader is obligated in the prayer of Rosh HaShana, so too, each and every individual is obligated in these prayers. Rabban Gamliel disagrees and says: Individuals are not obligated, as the prayer leader fulfills the obligation on behalf of the many.

§ The Sages taught in a baraita: From where is it derived that the soundings of Rosh HaShana must be performed with a shofar? The verse states: “Then you shall make proclamation with the blast of the shofar on the tenth day of the seventh month; on the Day of Atonement you shall make proclamation with the shofar throughout all your land” (Leviticus 25:9).

The Proper Order of the Shofar Blasts and in it 9 paragraphs
How many Tekiahs is one obligated to hear on Rosh HaShana? Nine. (This is) because it says "Teruah" by Yovel and Rosh HaShana three times. And every Teruah has a straight (blast) before it and a straight (blast) after it. And from tradition (the Sages) learned that all Teruahs of the seventh month, whether on Rosh HaShana or Yom HaKippurim of Yovel, (are) nine Tekiahs. We blow on each of them TR"T, TR"T TR"T.