For the Comcast customers who were confused earlier this week, when the cable company switched a bunch of channels to make room for more high definition channels, you can call 1-800-COMCAST or visit the Web site ComcastDigitalWorld.com, as suggested in TV editor's explanatory column of June 13 (post-gazette.com/pg/08165/889539-237.stm). Most callers to the Post-Gazette were wondering where MSNBC had gone: It's now Channel 183.