Timex Datalink or Timex Data Link is a line of early smartwatches manufactured by Timex and is considered a wristwatch computer. It is the first watch capable of downloading information wirelessly from a computer. As the name implies, datalink watches are capable of data transfer through linking with a computer. The Datalink line was introduced in 1994 and it was co-developed with Microsoft as a wearable alternative to mainstream PDAs with additional attributes such as water resistance, that PDAs lacked, and easy programmability. The watch was demonstrated by Bill Gates on 21 June 1994 in a presentation where he downloaded information from a computer monitor using bars of light and then showed to the audience the downloaded appointments and other data. The early models included models 50, 70, 150 and model 150s (small size). The model numbers indicated the approximate number of phone numbers that could be stored in the watch memory. These early models were, at the time of their introduction, the only watches to bear the Microsoft logo. The watches have been certified by NASA for space travel and have been used by astronauts and cosmonauts in space missions. There had been an evolution over the years as to the number and type of entries that can be stored in the various watch models as well as the mode of data transfer between computer and watch. At the time of its introduction the watch was considered high-tech.There is also the Timex Beepwear Datalink series, featuring wearable pagers using the Timex datalink platform which also function as electronic organisers.