After a judge signs an Oregon restraining order, the protective order does not actually go into effect until the other party (the "Respondent") is served. In Oregon, the sheriff will usually try to get this done immediately.
Once the other party physically receives the paperwork (been served), they are immediately restrained by the terms of the signed order. Note that sometimes difficulties finding the Respondent to serve them will result in a delay in getting the restraining order into effect.