Regarding the trumpeting to mark the end of the Sabbath, see Babylonian Talmud, Shabbath 114b; note especially Abbaye’s statement that this act was aimed at the common people. See also Maimonides, Mishnah Torah, Sefer Zemanim 5:20. In general, see the lengthy discussion by Saul Lieberman, Tosefta Ki-fshutah, part 4 (Moed) (New York, 1962), pp. 894–899. In particular, he notes that the custom of announcing the Sabbath by a blast of the ram’s horn continued among Babylonian Jewry at least until the time of the fourth century A.D. Raba amora (Babylonian Talmud, Abodah Zara 70a) The custom has been renewed in the cities and in various neighborhoods in modern Israel.