Radio Shack TRS-80 Model 4P
Released:November 1983
Weight:26 pounds
Price:US $1,790
Size:10 x 14 x 17 inches
CPU:Z-80A @ 4MHz
RAM:64K or 128K
Ports:Parallel, Serial, System bus
Display:9-inch, 80x24 text monochrome CRT
Storage:Two SSDD 180KB floppy drives
OS:TRS-DOS, LS-DOS, CP/M








While there were earlier portable TRS-80 computers, they were either pocket-sized with tiny 1-line displays, or laptop size with a small 8-line display. The Model 4P is the first portable TRS-80 computer with built-in 5 1/4-inch floppy drives and a full 80 x 24 character display.

The TRS-80 Model 4P is a portable version of the Model 4 desktop computer, which was released about five months prior. Of course, "portable" is a subjective description - it doesn't run on batteries, and it's big and heavy - weighing 26 pounds. It's better described as transportable or fully self-contained. But it does have a nice carrying handle.

While the differences between the Model 4 and Model 4P are mostly cosmetic, the 4P does have a smaller CRT display, and has no built-in operating system - the system must boot its operating system from a floppy disk or optional external hard drive.

Actually, two version of the Model 4P were created. The first, original version, and the later "gate array" versions, which in order to reduce costs and improve reliability, uses a few programmable IC chips to replace many simpler ones. They also changed the display color from white to green for improved readability.

Since it's portable, an optional 300 baud modem can be installed to connect with other computers via the telephone line.

An optional graphics card allows 640x240 or 512x192 hi-resolution dot-based graphics instead of just text.

Related Links

  • vintagecomputer.net
  • Model 4P Service Manual
  • "TRS-80 Home Page"
  • Ira Goldklang's TRS-80 Revived Site
  • Classic Tech - Vintage computers and related technology

  • Info World - Oct 1983
  • Info World - Nov 1983
  • NZ Bits and Bytes magazine - Oct 1984
  • TRS-80 Microcomputer News from TRS-80 Color Computer Archive

  • 1984 TRS-80 Catalog
  • Advertisement - Dec 1983
  • Advertisement - Apr 1984
  • Advertisement - Jun 1984


    • Original motherboard - version I


    "Gate Array" motherboard - version II


    History of the Radio Shack Computers

    • 1921: - Radio Shack begins as a one-store retail and mail-order company catering to ham operators and electronics buffs.
    • 1963: - Charles Tandy buys the chain of stores, and within two years turned a $4 million dollar loss into a $20 million dollar profit.
    • 1977: August - Radio Shack announces the TRS-80 Model I microcomputer for US$600.
    • 1977: September - One month after launching the TRS-80, 10,000 are sold.
    • 1979: May - Tandy/Radio Shack announces the TRS-80 Model II.
    • 1979: October - Radio Shack begins shipping the TRS-80 Model II to users.
    • 1980: July - Radio Shack introduces the TRS-80 Model III, priced from US$700 to US$2500.
    • 1980: July - Radio Shack introduces the TRS-80 Color Computer, and sells for US$400.
    • 1980: July - Radio Shack introduces the TRS-80 Pocket Computer. Price is US$230.
    • 1981: January - Radio Shack ceases production of the TRS-80 Model I, and recalls units from the US market, due to failure to meet new FCC radio-frequency interference regulations.
    • 1982: January - Radio Shack introduces the TRS-80 Model 16, with 8-inch floppy drives, and optional 8-MB hard drive.
    • 1982: January - Radio Shack introduces the TRS-80 Pocket Computer, Model PC-2, for US$280.
    • 1983: March - Radio Shack announces its TRS-80 Model 100 portable computer. Price is US$799 for 8KB version, to US$1134 for the 32KB version.
    • 1983: May - Radio Shack introduces the TRS-80 Model 4, for US$2000.
    • 1983: October - Tandy/Radio Shack announces the "transportable" TRS-80 Model 4P, for US$1800.
    • 1983: Radio Shack introduces the TRS-80 Pocket Computer, Model PC-4, replacing the PC-1, for US$70.
    • 1983: Tandy releases the TRS-80 Model 2000, which uses the Intel 80186 microprocessor.
    • 1983: Radio Shack unveils the TRS-80 Model 12 at the CP/M '83 Show. Price is US$3200.
    • 1985: March - Radio Shack introduces the Tandy 6000 multiuser system. It features Z80A and 68000 processors, 512 KB RAM, 80x24 text, graphics, 1.2-MB 8-inch disk, optional 15 MB hard drive, TRS-DOS, or XENIX 3.0. It supports up to 9 users.
      Source: Chronology of Events in the History of Microcomputers



    Return to the Obsolete Technology Homepage