Comcast just issued a formal announcement of the digital switch mentioned last week.

The company is launching its conversion of expanded basic channels to a digital format starting with certain "test" areas and about half of the channels in the 30 to 70 range. To get all the converted channels, expanded basic customers will need a Comcast converter device on all of their televisions.

Starting tomorrow, this will be in effect in Enumclaw, Covington, Black Diamond and Cedar Downs in King County; Mill Creek, Lynnwood, Mountlake Terrace, Brier and Clearview in the north end; and in Pierce, parts of Buckley, Bonney Lake, Carbonado, Eatonville, Graham, Orting, Prairie Ridge, Roy, South Prairie and Wilkeson.

The first channels to go digital there will be AMC, Animal Planet, Bravo, Cartoon, CMT, E!, Food, FX, HGTV, History, Lifetime, MSNBC, MTV, Oxygen, Sci-Fi, TLC, TNT, Travel, TruTV and Versus.

Expect the switch next in Auburn, Kent, Federal Way, Algona, Pacific, Puyallup, Parkland, Fort Lewis, Tukwila, SeaTac, Burien and Vashon Island.

Those areas will see the swtich beginning the first week of April, and all expanded channels there should be converted to digital around the first week of May, spokesman Steve Kipp said.

Comcast expects to convert all of its Washington expanded basic customers by the end of the year.

Customers may still be able to get some of the channels without a converter device, if they're not encrypted by Comcast. The company hopes to encrypt them all but won't do so immediately.

Here's more backgrond:

The March 5 item announcing the timing.

The first story reporting Comcast's digital switch here and looking at reasons why it's happening.

A list of FAQs on the Comcast switch, plus a few more questions and answers about the converter boxes and encryption.

Here's Comcast's list of channels making the switch. The column on the left shows the first batch that will be converted to digital and the column on the right shows the second batch.