on September 27, 1993, effectively acting as part-time simulcast feeds with added first-run Spanish-language movies (mostly from Mexico, Argentina and Spain), and Spanish dubs of HBO's non-sports-event original programming—quickly gained interest from providers, expanding to an additional 35 cable systems in various U.S. markets in the weeks following its debut. Other services HBO HD HBO HD (originally called HBO HDTV from March 1999 until April 2006) is a high definition simulcast feed of HBO that broadcasts in the 1080i resolution format. HBO maintains high definition simulcast feeds of its main channel and all six multiplex channels. HBO HD is available on all major cable television providers including, among others, Charter Communications (including systems once owned by former HBO sister company Time Warner Cable); Comcast Xfinity (which, in 2016, began downconverting HBO, Cinemax and other cable channels transmitting in 1080i to 720p60); Cox Communications and Optimum; as well as DirecTV; AT&T U-verse; and Verizon FiOS. From the 2008 rollout of HD simulcasts for the HBO multiplex feeds until the mid-2010s, the majority of pay television providers that carried HBO HD generally offered only the main channel in high definition, with HD carriage of the multiplex channels varying by market. , most providers transmit all seven HBO multiplex channels in HD, either on a dedicated HD channel tier separate from their SD assignments or as hybrid SD/HD feeds. Home Box Office, Inc. announced plans to launch a high definition simulcast feed on June 12, 1997, with initial plans for a rollout to television providers as early as the Summer of 1998, when electronics manufacturers planned to begin retailing their initial line of HD-capable television sets. HBO began transmitting a high definition simulcast feed on March 6, 1999, becoming the first American cable television network to begin simulcast their programming in the format. For the first 23 months of its existence, the HD feed only transmitted theatrical films from the network's programming suppliers (initially accounting for about 45% of its available feature film output, expanding to around 60% by early 2001) and HBO's in-house original movies in the format, as existing widescreen prints of those films were already scalable in the 16:9 widescreen aspect ratio and could readily be upconverted to HD resolution. Original programming began to be made available in HD on January 14, 2001, when the network commenced a 13-week Sunday "encore" presentation of the second season of The Sopranos in