dissenting:
Although I join the Chief Justice’s dissenting opinion, I write separately to emphasize my disagreement with the court’s unquestioning acceptance that suppression of the pen register tape is necessary to effectuate the purpose of art. II, sec. 7, of the Colorado Constitution.
Smith v. Maryland, 442 U.S. 735, 99 S.Ct. 2577, 61 L.Ed.2d 220 (1979), was decided in June 1979, approximately one year before the pen register was installed on the defendant’s home telephone. At that time, prosecutors and police officers were on notice that the nation’s highest court had determined that the installation and use of a pen register was not a search within the meaning of the fourth amendment, and therefore no warrant was required.
On May 20, 1980, the date the pen register was installed, neither we nor the Colorado Court of Appeals had expressed any views concerning the constitutionality of installing a pen register without first obtaining a warrant. Also on that date, we had not decided Charnes v. DiGiacomo, 200 Colo. 94, 612 P.2d 1117 (1980), a case upon which respondent and the majority rely to support their claim of “legitimate expectation of privacy.”
The exclusionary rule is not a personal constitutional right, but a remedy adopted by the United States Supreme Court to *152protect the fourth amendment right of citizens. By denying admission of evidence obtained through unlawful police activity, it was believed law enforcement officers would be deterred from future violations of the fourth amendment.
However, the exclusionary rule has not been interpreted by the United States Supreme Court as requiring exclusion of all illegally seized evidence. Stone v. Powell, 428 U.S. 465, 96 S.Ct. 3037, 49 L.Ed.2d 1067 (1976). For example, the rule has not been applied when police act in good-faith reliance upon a statute or ordinance that is subsequently held to be unconstitutional. United States v. Peltier, 422 U.S. 531, 95 S.Ct. 2313, 45 L.Ed.2d 374 (1975); Michigan v. DeFillippo, 443 U.S. 31, 99 S.Ct. 2627, 61 L.Ed.2d 343 (1979). Application of the exclusionary rule has been restricted to those areas where its remedial objectives are thought most efficaciously served. United States v. Calandra, 414 U.S. 338, 94 S.Ct. 613, 38 L.Ed.2d 561 (1974).
Here, application of the rule has no support in the prior decisions of this court or in logic, because the challenged act of the law enforcement official took place at a time when the United States Supreme Court had addressed the issue of pen registers, and the evidence was obtained by the district attorney acting in the reasonable belief that his conduct did not violate the constitutional rights of the defendant.
The deterrent purpose of the exclusionary rule “assumes that the police have engaged in willful, or at the very least negligent, conduct which has deprived the defendant of some right.” United States v. Peltier, 422 U.S. 531, 539, 95 S.Ct. 2313, 2318, 45 L.Ed.2d 374. If deterrence of unlawful police conduct is the bedrock on which the exclusionary rule rests, and I believe it is, then 'evidence should be suppressed only where a law enforcement officer had knowledge, or may properly be charged with knowledge, that it was obtained in an unconstitutional manner. It is clear to me that where law enforcement officers act in conformity with, and in reliance upon, a decision of the United States Supreme Court, application of the exclusionary rule is not called for. The majority opinion ignores the reason for the rule and applies it in a mechanistic and inappropriate fashion.
Indeed, the use of the exclusionary rule in this case demonstrates why a good-faith exception to the rule should be applied. I cannot think of a sounder basis for law enforcement officers to act upon than a decision of the United States Supreme Court. To exclude evidence based upon such reliance because we later conclude that there is a violation of the Colorado Constitution is to punish law enforcement officers for a lack of prescience that warrants neither criticism nor censure. In effect, the court penalizes society by interfering in the truth-seeking function of a criminal trial by barring relevant and trustworthy evidence. In no way does application of the exclusionary rule in this case serve the deterrent function that is the foundation upon which the rule rests. I respectfully dissent.
I am authorized to say that CHIEF JUSTICE ERICKSON joins in this dissent.