12 CFR 229.30: Electronic checks and electronic information.

(a) Checks under this subpart. Electronic checks and electronic returned checks are subject to this subpart as if they were checks or returned checks, except where “paper check” or “paper returned check” is specified. For the purposes of this subpart, the term “check” or “returned check” as used in Subpart A includes “electronic check” or “electronic returned check,” except where “paper check” or “paper returned check” is specified.

(b) Writings. If a bank is required to provide information in writing under this subpart, the bank may satisfy that requirement by providing the information electronically if the receiving bank agrees to receive that information electronically.