Could a telephone cable explain Kiska's radio silence?

Could Kiska's radio silence have meant that the Japanese were using a telephone cable?

Installing a cable through the American blockade would itself have been an extraordinary engineering operation; the combined signs of evacuation warranted reconnaissance.

Radio silence could have another explanation, including a switch to cable communications. The American blockade, however, would have made laying such a cable unusually difficult. It would have required a rapid operation by small fast ships or a submarine. Together with the other signs of evacuation, the loss of radio traffic warranted scouting flights before the landing.