1) Transitional Deacons, those men studying for the Priesthood are ordained to the "Major Order" (cleric) of diaconate. It is at this point that the promise of celibacy is received by the diocesan bishop or his representative.
2) Permanent Deacons, A man must be at least 35 years old, and have been active in parish life for a minimum of 5 years. (Most likely in the roles of Reader, and Extraordinary Minister of Holy Communion.) These men are recommended by members of the parish and sponsored by the Parish Priest. They then enroll in a program which includes formation, and a full course of study (which lasts approximately 4-5 years.) If married, their wives are interviewed, the role of a "permanent" Deacon is explained, and she must agree to her husband's application, and attend a series of retreats, and days of formation.
[ Should the applicant not be married at the time of Ordination to the Diaconate, he must promises to live a celibate life. If the man is married, he continues to live a normal married life. If not retired, he continues to follow his career. Should his wife pre-decease him, he is obliged to live a celbate life.]