Related for Rosh Hashanah 68:17

The order of the horn tones: Three [times] three [tones] each. [heard one] six tekibt and three terubt. of nine people at once, he has fulfilled his duty. Heard [a] he six tekibt. of this and the teru'a of that, even with interruptions, even throughout the day, so he did his duty. He blew a teki'a, a teru'a, and then he blew a teru'a again and then a teki'a, like this he only has one horn to He blew a teki'a, a teruä and [then again] a tekiä in one breath, so he has obeyed the duty