In Oregon, the right to the assistance of counsel during custodial interrogation is founded in the right against self-incrimination as guaranteed in Article I, section 12, of the Oregon Constitution, and the Fifth Amendment to the United States Constitution. To guard the constitutionally guaranteed right against self-incrimination, police are required to give Miranda warnings to persons in custody or otherwise compelling circumstances. The commonly known rights that are read to people come from a case called Miranda v. Arizona which was decided in 1966. People have become so used to hearing these rights that they seem to have stopped listening to what they are actually being told. If police read you your rights, you should invoke them immediately and ask to speak with a lawyer.
Police must give Miranda warnings to a person who is in full custody or in circumstances that create a setting which judges would and officers should recognize to be compelling. In deciding whether a person's encounter with police became compelling, thus triggering a Miranda warning requirement, a court must consider a host of factors, including: (1) the location of the encounter; (2) the length of the encounter; (3) the amount of pressure exerted on the defendant; (4) the defendant's ability to terminate the encounter, (5) the number of officers and police cars at the scene, (6) the use of physical force or confinement during questioning, (7) and the demeanor of the investigating officer. If you are in a situation where police are questioning you, you should ask for a lawyer even if you have not been read your rights. Police will purposely question you in a low key manner so you make incriminating statements.
You do not have to speak with the police whether you are in custody or not.