The term 'EARLY SMARTPHONE MODEL' can be summarized as the Treo, a four-letter word. The Treo was a series of smartphones developed by Palm, Inc. and released in 2002. It was one of the first smartphones to combine the functions of a mobile phone and a PDA into a single device. It was also the first to feature a full QWERTY keyboard and a touchscreen. The Treo was popular among business users and was eventually replaced by the Palm Pre in 2009.