Cablevision Systems Corp. confirmed reports that it is testing a new service tier that caps cable modem download speeds at 20 Mbps, and 2 Mbps in the upstream. Cablevision’s flagship tier is capped at 10 Mbps down/1 Mbps up.

Cablevision’s Optimum Online unit will operate a beta test of the service through October 1, 2005 in the Long Island, N.Y. area. Customers who participate are expected to provide Cablevision with periodic feedback.

According to a letter from Cablevision, participating customers will be given the opportunity to upgrade to a new tier of service. Cablevision did not mention pricing on the service, should it decide to move beyond a trial.

Earlier this year, Cablevision kicked off a 50 Mbps service (expandable to 100 Mbps) for commercial customers in Oyster Bay, N.Y., using an out-of-band technology from Narad Networks. Cablevision has not disclosed any plans to use the Narad platform to support residential data subscribers.

Although cable operators have been downplaying competition with Verizon, some have increased speeds in markets targeted by the telco’s FiOS fiber-to-the-premises (FTTP) platform.