Cable operators have told the FCC not to mandate that they implement the SHAKEN/STIR* default robocall blocking regime, saying a more flexible rollout is best way to go.

The FCC, as part of its push to crack down on illegal and unwanted robocalls--which number in the billions annually--clarified back in June that carriers can block calls before they reach customers' phones, and strongly suggested that carriers implement the voluntary SHAKEN/STIR ASAP. The FCC also signaled that if they didn't, that would become a mandate, essentially taking the "voluntary" out of voluntary.

Democrats in Congress and public advocacy groups have been pushing for a mandate, but NCTA-The Internet & Television Association, pushed back in comments filed Aug. 23.

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NCTA said it is not like carriers are "stubbornly refusing" to implement the call-blocking technology. It told the FCC that all carriers have a strong incentive to adopt the regime because unwanted robocalls make for unhappy customers. It also pointed out that it was the industry that came up with the SHAKEN/STIR standards and governing authority.

Cable ops also pointed out it is not like just flipping a switch, but requires a number of steps, including having to:

•"procure/modify software and hardware, as needed, to incorporate SHAKEN/STIR capabilities;

• "implement on its own network the capability to sign calls originating from its subscribers;

• "implement on its own network the capability to verify calls terminating with its subscribers; and

• "conduct lab tests with other providers to ensure compatibility for exchange of authenticated calls, and possibly conduct tests in a production environment as well."

"Requiring a company to implement SHAKEN/STIR before it is economically and technologically feasible for that company will only lead to ineffective and inefficient actions," NCTA said.

ACA Connects, which represents the smaller operators for whom the steps would be harder to take, has also said there appears to be no need for a "rigid" mandate at this time.

* SHAKEN/STIR stands for "Secure Telephony Identity Revisited"/"Secure Handling of Asserted information using toKENs"