page_title: TRS-80 Model 4
section_title: Model 4
hierarchical_section_title: TRS-80 Model 4 / Model 4
caption_attribution_description: English: TRS-80 Model 4
context_page_description: The TRS-80 Model 4 is the last Z80-based home computer family by Radio Shack, sold from April 1983 through autumn 1991.
context_section_description: Tandy Corporation introduced the TRS-80 Model 4 in April 1983 as the successor to the TRS-80 Model III. The Model 4 has a faster Z80A 4 MHz CPU, larger video display of 80 columns by 24 rows, bigger keyboard, and can be upgraded to 128KB of RAM. It is compatible with Model III software and CP/M application software. 
  A diskless Model 4 with 16KB RAM cost $999; with 64KB RAM and one single-sided 180K disk drive it cost $1699; with 64KB RAM and two drives it cost $1999. An upgrade for Model III owners cost $799 and provided a new motherboard and keyboard.
  The Model 4's first appearance in the RadioShack catalog stated: "Yes, it looks like a Model III, but it's much much more. Compare the price and features of our amazing new Model 4 to any other computer in its class. You'll find that for power, versatility, and convenience it is a true breakthrough. To add the same features to other computers, you'd have to pay a whole lot more." Commenting on its unexpected longevity as a RadioShack product and object of aftermarket support by third-party companies, in May 1987 80 Micro magazine remarked, "Even when it was introduced in 1983, the Model 4 was seen as a last gasp for the TRS-80 line."
caption: TRS-80 Model 4 
  (1983 non-gate array version)
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