CBS telecast few programs in color, either locally or through the network, until the mid-1960s when color television sets became more affordable to the American public. In May 1997, the station adopted the "CBS 2" branding, along with sister stations KCBS-TV in Los Angeles and WBBM-TV in Chicago, while retaining a unique and distinctive logo. WCBS-TV's over-the air signal was not affected by the September 11 terrorist attacks that destroyed the World Trade Center. Unlike its competitors, channel 2 had long maintained a full-powered backup transmitter at the Empire State Building after moving its main transmitter to the North Tower of the then-new World Trade Center in 1975. The station's coverage of the attacks was also simulcast nationally on Viacom (which owned CBS at the time) cable network VH1 that day. In the immediate aftermath of the attacks, WCBS-TV was briefly the only full-coverage over-the-air television service operating in New York City, although the station lent transmission time to other stations who had lost their transmitters until they found suitable backup equipment and locations. The backup transmitter had been put into operation once before, when the World Trade Center bombing of February 26, 1993, knocked most of the area's stations off the air for a week. Digital era WCBS-TV discontinued regular programming on its analog signal, over VHF channel 2, at 2 p.m. on June 12, 2009, as part of the federally mandated transition from analog to digital television. The station moved its digital signal from its pre-transition UHF channel 56, which was among the high band UHF channels (52–69) that were removed from broadcasting use as a result of the transition, to channel 33, using PSIP to display WCBS-TV's virtual channel as 2 on digital television receivers. Since the station qualified for the nightlight clause in the DTV Delay Act, WCBS kept its analog signal on for one month to provide public service announcements, starting at 3 p.m. on June 12 and permanently shutting it down during the early morning hours of July 13, 2009; this possibly made it the last full power NTSC broadcast television station in the United States to discontinue analog transmissions. Digital subchannel 2.2, branded as CBS New York Plus, was launched in November 2011 as a 24-hour news channel drawing upon the resources of WCBS-TV, WCBS radio (880 AM), WINS (1010 AM), and WFAN (660 AM). The Plus service was eventually planned to be