A debate has been brewing for the last few years over the issue of cell phone evidence. In Ontario there have been decisions holding that evidence about cell phone records, including interpreting the records, identifying tower locations and explaining the way in which phones communicate with towers is expert evidence requiring a voir dire; those decisions also held that the usual witnesses (corporate security personnel who gather the evidence and have, for several years testified in this area) are not "experts" on this issue: see R v Spackman,  OJ No 1066 (SCJ) and R v MacFarlane,  OJ No 4858 (SCJ).
In the recent case of R v Hamilton, 2011 ONCA 399 the Ontario Court of Appeal has sided with the Manitoba approach, implicitly overruling MacFarlane and Spackman - at least in part. In Hamilton, for the first time on appeal, the appellants argued that the trial judge erred in admitting the evidence of non-engineers and erred by failing to conduct a voir dire. The Court of Appeal rejected this argument on the basis, inter alia, that the evidence in question is not expert evidence:
...we are satisfied that the evidence given by the three employees of the carrier companies was factual evidence, not opinion evidence. Each of them, by reason of their knowledge, observation and experience in dealing with cell phones for their respective companies could give the testimony they provided without being qualified as experts. They could testify about the times each appellant’s cell phone registered, the number calling and the number called, the duration of the call and the location of the towers at which the calls registered. These were factual details on which the carriers based their billing practices. Further, these employees had the knowledge and experience to testify about the general rule and its exceptions. They did not have to understand the scientific and technical underpinnings of the rule or have an engineering degree to give this evidence.It is perhaps understandable why some courts in years past treated this kind of evidence as opinion evidence. The introduction of cell phone evidence in criminal trials was in its infancy. Now, with the benefit of hindsight, we know that this evidence is routinely admitted: see, for example, R. v. Tomlinson,  O.J. No. 817 (S.C.J.), R. v. H.B.,  O.J. No. 1088 (S.C.J.), R. v. Smith,  O.J. No. 4544 (S.C.J.).Even if evidence about the general rule and its exceptions could at one time have been considered opinion evidence, it is now simply factual evidence that witnesses with the knowledge and experience of Mr. Rickard, Mr. Iaccio and Ms. Hopper can testify about. They were not proffering a novel scientific or behavioral theory that was open to debate. They were testifying about uncontroversial facts related to the operation of cell phone networks. As the trial judge noted, their evidence was essentially the same as the evidence that could have been given by an engineer. Indeed, an engineer, Mr. Wang, gave largely the same evidence about the general rule at the preliminary inquiry. With the benefit of that testimony, no appellant insisted that an engineer give this evidence at trial.Importantly, none of the three cell phone witnesses was asked to give an opinion about the precise location of an appellant’s cell phone when a particular call was made or received. Evidence of that nature might well be opinion evidence and subject to the Mohan criteria: see R. v. Ranger, 2010 ONCA 759, at para. 17. Testimony about the general rule and its exceptions is not opinion evidence, and thus no voir dire was necessary.Accordingly, we do not give effect to the appellants’ challenge to the admissibility of the cell phone evidence. [paras 277-284] [emphasis added].