America Online Inc. [AOL] and Hughes Network Systems Inc. [GMH] plan to start Beta tests of their planned AOL Plus Powered by DirecPC service in about 16 markets, including New York and San Francisco, later this month.

They plan to begin the full service later this year, but the tests beginning later this month will concentrate more on the technology, said a spokeswoman for AOL.

HNS is designing its two-way DirecPC system to provide Internet access at uplink speeds between 128 kilobits per second and 256 kbps and downlink speeds of 40 megabits per second.

In addition to AOL’s marketing of the AOL Plus service, HNS is planning to market DirecPC through its DirecTv sister company and through the 26,000 retailers and distributors who carry DirecTv and sell HNS satellite receivers. HNS and DirecTv are subsidiaries of Hughes Electronics Corp. [GMH].

AOL’s spokeswoman said the company will use high-speed cable TV and other broadband media for the AOL Plus service, in addition to HNS’s satellite access and distribution.