N.Y. Comp. Codes R. & Regs. tit. 17, § 505.6 – Notice of hearing.

(a) The notice of hearing shall contain a statement of the legal authority under which the proceeding is to be held and shall specify the notice or notices of violation to be heard.
(b) The notice of hearing shall specify the time and place of the hearing, and shall set a date for a hearing via first-class mail or electronically. If the matter is to be heard on the papers, the respondent will be sent a notice of opportunity to be heard containing a return date for all submissions.
(c) Service of a notice of hearing or a notice of opportunity to be heard shall be by personal service, electronically, or by first-class mail. Any notice not returned by the post office for nondelivery or electronic notification of failed delivery shall be presumed received by the respondent. Any notice of hearing returned by the post office as having been refused by the respondent shall be deemed properly served. The service date is the date a notice is served personally, electronically, or by first-class mail.