Oregon Revised Statutes Property Rights and Transactions § 90.150

(1) Verbal notice that is given personally to the landlord or tenant or left on the landlord's or tenant's telephone answering device.

(2) Written notice that is personally delivered to the landlord or tenant, left at the landlord's rental office, sent by facsimile to the landlord's residence or rental office or to the tenant's dwelling unit, or attached in a secure manner to the main entrance of the landlord's residence or tenant's dwelling unit.

(3) Written notice that is delivered by first class mail to the landlord or tenant. If the notice is mailed, the notice shall be considered served three days after the date the notice was mailed.

(4) Any other method reasonably calculated to achieve actual receipt of notice, as agreed to and described in a written rental agreement.