TORONTO - The official arrival of a system designed to block certain types of nuisance calls was greeted Thursday by telecom professionals as a good move - but only a partial solution to a complex problem that bedevils Canadian consumers.

The Canadian Radio-television and Telecommunications Commission gave carriers until Dec. 19 to put in place universal call blocking' or an equivalent system at the network level to stop blatantly spoofed numbers.

Bell Canada and Rogers Communications confirmed Thursday that they updated their systems with universal call blocking by the deadline while Telus said it has opted for a an alternative filtering system to meet the CRTC's criteria.

Ofir Smadja, founder and CEO of a Toronto-based company that provides professional services to the telecom industry, said he thinks universal call blocking and other regulated systems will reduce how many spam calls get through.

“But would (they be) completely eliminated? I don't think so,” Smadja said in an interview.

CRTC chairman Ian Scott has conceded that there's probably no way to rid Canadian phone networks of all unwanted or fraudulent calls, just as police can never stop crime in general.

“You don't eliminate crime. You reduce it. You protect consumers against it,” Scott said in a CBC Radio interview broadcast Monday.

Smadja said he agrees with Scott's description of the situation and noted that the United States is also struggling to find an answer to nuisance calls that have become increasingly common in recent years.

He noted that the U.S. Federal Communications Commission has given its carriers until Dec. 31 to implement a system to verify a caller's identity (a protocol known by the acronym STIR/SHAKEN in Canada or SHAKEN/STIR in the United States.)

“Yes, we do know it works somewhat or partially, in the States, but it's still not fully functional,” Smadja said.

Smadja said there are two short-comings of this approach, which requires the carrier handling the original call to verify that it comes from a legitimate number belonging to a customer.

One problem, he said, is that it's possible for criminals to set up fake companies to obtain legitimate numbers, thereby subverting the verification system.

Another problem, he said, is that the system may not be able to authenticate legitimate callers if the STIR/SHAKEN verification messages don't travel across an internet protocol network from beginning to end

“And we know the industry still has legacy types of circuits that will not be able to support STIR/SHAKEN.”

Nevertheless, the CRTC announced this month that Sept. 30, 2020, is its target for having STIR/SHAKEN in place in Canada.

The CRTC also wants carriers to put in place a system for tracing the origin of spam calls - and has given them until March 2020 to present a report of the traceback system.

An executive with Seattle-based Hiya Inc., which provides free and subscription-based apps for iOS and Android phones, as well as a carrier-grade system used by AT&T, said he thinks regulators like CRTC and FCC are on the right track.

“What we do is, basically, partner with the carriers to be as compliant as possible to these regulations. So these are all steps in the right direction,” Kush Parikh, Hiya's chief operating officer, said Thursday in an interview

“But in no scenario is this a silver bullet. . . . It's a bit of a cat-and-mouse game with the scamsters.”

Hiya estimates U.S. users received an average of 14 spam calls per month this year, roughly double the American experience last year. By comparison, the 2019 Canadian average is six spam calls per month per user.

This report by The Canadian Press was first published Dec. 19, 2019.

- with files from Terry Pedwell in Ottawa