website/content/museum/tandy-radio-shack-trs-80-model-4p.md

---
title: Tandy Radio Shack TRS 80 Model 4P
categories:
- Computers
types:
- Portable
origins:
- U.S.A.
years:
- '1983'
cpus:
- Z80A
params:
  name: TRS 80 Model 4P
  image: /media/museum/photos/tandy_model4p_system_2.jpg
  company: /companies/tandy-radio-shack
  company_name: Tandy Radio Shack
  specs:
  - label: NAME
    value: TRS 80 Model 4P
  - label: MANUFACTURER
    value: Tandy Radio Shack
  - label: TYPE
    value: Portable
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: October 1983
  - label: BUILT IN LANGUAGE
    value: None
  - label: KEYBOARD
    value: Typewriter style, 70 keys with numeric keypad and arrow keys
  - label: CPU
    value: Z80A
  - label: SPEED
    value: 4 MHz
  - label: RAM
    value: 64 or 128 KB
  - label: ROM
    value: 4 KB
  - label: TEXT MODES
    value: 32 or 64 x 16 / 64 x 40 / 80 x 24
  - label: GRAPHIC MODES
    value: None
  - label: COLORS
    value: Monochrome
  - label: SOUND
    value: Buzzer
  - label: I/O PORTS
    value: Parallel, Serial, Expansion bus
  - label: BUILT IN MEDIA
    value: |-
      2 x 5.25'' SS SD 180 KB floppy drives\
      Very late models had double-sided TEAC drives
  - label: OS
    value: TRS-DOS 6.0 to 6.2, LS-DOS 6.3, CP/M
  - label: POWER SUPPLY
    value: Built-in power supply unit
  - label: PERIPHERALS
    value: Built-in 300-baud modem, external HDD
  - label: PRICE
    value: $1,790
  tabs:
  - photos
  - hardware
  - emulators
  - links
  photos:
  - title: MODEL 4P
    subtitle: ''
    text: ''
    image: /media/museum/photos/tandy_model4p_front_ebay_2.jpg
  - title: FRONT
    subtitle: ''
    text: ''
    image: /media/museum/photos/tandy_model4p_front_ebay_1.jpg
  - title: KEYBOARD
    subtitle: ''
    text: ''
    image: /media/museum/photos/tandy_model4p_keyboard_1.jpg
  - title: BACK
    subtitle: ''
    text: |-
      from left to right:

      \- RS232C connector\
      \- I/O bus\
      \- parallel port
    image: /media/museum/photos/tandy_model4p_back_1.jpg
  - title: CLOSED
    subtitle: ''
    text: ''
    image: /media/museum/photos/tandy_model4p_closed_1.jpg
  hardware:
  - title: REMOTE UNIT ACTIVE
    subtitle: Serial# 26-1210
    text: |-
      This rare unit is meant for teachers to control up to 16 TRS-80 Model 1 from a another TRS-80 equiped with min-disk. All the controled TRS-80 model 1 must be equiped with Level II.

      It cost 2895fr (France, 1981)
    image: /media/museum/hardware/tandy_trs80-m1_remote-unit-active.jpg
  - title: NETWORK II BOX
    subtitle: p/n 26-1211
    text: |-
      This box allowed up to 16 TRS computer to be networked. Three network boxes were released by Tandy (I, II and III).\
      The Network II required verbal communication between the server operator and the remote user, and data transfer had to be completed one user at a time.\
      The network III allowed automated control of the network so that users could easily access programs and data stored on the server's storage device.

      Thanks to **David Sutherland** for the pictures.
    image: /media/museum/hardware/tandy_network2_s1.jpg
  - title: DMP-200
    subtitle: ''
    text: 80-column, 100 cps dot matrix printer.
    image: /media/museum/hardware/tandy_model3_dmp200_s1.jpg
  - title: DAISY WHEEL PRINTER II
    subtitle: Serial# 26-1158
    text: |-
      This is a high-quality printer meant to be used with wordprocessors. Some interchangeable daisy-wheels were available (Courrier, Elite, Madeleine). It could print 163 characters per line (34cm), at a 43 cps rate.

      It cost 9595fr (France, 1981)
    image: /media/museum/hardware/tandy_trs80-m1_daisy-wheel-printer-2_1.jpg
  - title: LINE PRINTER I
    subtitle: Ref# 26-7017
    text: |-
      This printer was a custom version of the Oki Microline 80.\
      Printed lower and upper case on paper rolls or listing paper (24cm wide) from 40 to 80 columns/line, at a speed rate of 28 lines/minute.

      It cost 716 Euros in 1981 (France).
    image: /media/museum/hardware/tandy_model1_lineprinter1_s1.jpg
  - title: LINE PRINTER III
    subtitle: Serial# 26-1156
    text: This printer can print lower and upper case, at a speed rate of 120 c/s, on paper up to 38cm wide. It is conceived for intensive use ! It cost 9950fr in 1981 (France).
    image: /media/museum/hardware/tandy_trs80-m1_line-printer-3_1.jpg
  - title: LINE PRINTER VI
    subtitle: Serial# 26-1166
    text: |-
      This large printer can print lower and upper case, graphic characters and symbols at a speed rate of 100 c/s ! This is definately a professional printer.

      It cost 5495fr in 1981 (France).
    image: /media/museum/hardware/tandy_trs80-m1_line-printer-6_1.jpg
  - title: TP-10 THERMAL PRINTER
    subtitle: Box
    text: ''
    image: /media/museum/hardware/tandy_trs80_tp-10_thermal-printer_box.jpg
  - title: EXATRON
    subtitle: Stringy Floppy drive
    text: |-
      The Exatron Stringy Floppy (ESF) was a low-cost data—storage system that fitted the gap, between cassettes and disk drives.\
      The system was based on a miniature endless—loop tape cartridge called a "wafer".\
      The amount of data that could be recorded on a wafer depended on the length of tape in it, typically, a 50—foot wafer could hold at least 40 KB of programs or data.

      **Matt** reports to us:\
      A curiousity about the model 1, CPU SPEED had a direct relatonship with STORAGE CAPACITY. if you doubled the clock speed of your MODEL 1 CPU you doubled the amount of data you could store on your stringy floppies. this is a feat that no other computer no matter how many ghz you have in your PC can do today without using compression.

      Thanks to **David Sutherland** for the pictures
    image: /media/museum/hardware/tandy_model3_exatronwafer_s1.jpg
  emulators:
  - title: David Keil's TRS-80 Model III/4/4P Emulator Page
    url: http://discover-net.net/~dmkeil/trs80/model4.htm
    platform: MS DOS
    text: This program emulates a complete TRS-80
  - title: Matthew Reed's TRS-80 Emulator Web Site
    url: http://www.arrowweb.com/mkr/
    platform: MS DOS
    text: This page offers shareware versions of a TRS-80 Model 4 emulator and a TRS-80 Model 1-2 emulator
  - title: TRS-80 Model III/4 Emulator
    url: http://www.vavasour.ca/jeff/trs80.html#model4
    platform: MS DOS
    text: This TRS-80 Model III/4 Emulator is a commercial product
  - title: 'xtrs: TRS-80 Model I/III/4 Emulator for Unix'
    url: http://www.tim-mann.org/xtrs.html
    platform: Unix / Linux
    text: xtrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for Unix and the X Window System
  - title: TRS-80 Level I BASIC in a browser
    url: http://www.vavasour.ca/jeff/trs80.html#simulator
    platform: Other platform
    text: With this Java emulator, you'll be able to write a BASIC program directly in your browser!
  - title: Ira Goldklang's TRS-80 Revived Pages
    url: http://www.trs-80.com/trs80-e.htm
    platform: Multiplatform
    text: A complete list of TRS-80 emulators for various platforms !
  - title: MESS
    url: http://www.mess.org
    platform: Multiplatform
    text: MESS emulator also emulates a TRS-80 systems
  links:
  - title: 8bit-micro.com - Online TRS-80 Computer Magazine
    url: HTTP://WWW.8BIT-MICRO.COM
    text: Online Magazine dedicated to the TRS-80 and other Vintage - Monthly Issues
  - title: David's TRS-80 Page
    url: http://freespace.virgin.net/david.sampson/
    text: ''
  - title: Ira Goldklang's TRS-80 Revived Pages
    url: http://www.trs-80.com/
    text: Lof of infos about all TRS-80 computers
  - title: Java TRS-80 Model 1 BASIC Interpreter
    url: http://ganley.org/software/trs80.html
    text: ''
  - title: Mike's Personal Computer Museum
    url: http://personal.nbnet.nb.ca/mclays/trsmod1.html
    text: Level 1 & 2 Basic summaries, Tandy time-lines, price-list, etc ... !
  - title: RadioShackCatalogs.com
    url: http://www.RadioShackCatalogs.com
    text: Here, you can actually/virtually flip-through the pages to view the content of every RadioShack catalog!
  - title: The TRS-80 Home Page
    url: http://www.kjsl.com/trs80
    text: Full of infos
  - title: Tim Mann's TRS-80 Page
    url: http://www.tim-mann.org/trs80.html
    text: Infos, tools and home of xtrs, a Model I/III/4 emulator for Unix
  - title: Web Wiz CAPTCHA
    url: http://www.webwizcaptcha.com
    text: Discussion about Tandy computers
  comments:
  - author: Steve mills (Corvallis or)
    date: Monday 4th June 2018
    text: Trs80 model 4p for sale
  - author: CJ (Virginia)
    date: Sunday 1st April 2018
    text: |-
      I own a 4P myself, and thought I would add some more specific technical details -

      The 180K disk drives it uses are Tandon brand drives, model TM50-1, belt-driven.\
      The Z80A CPU is SGS Thompson branded, model Z8400AB1.
  - author: Jeff Gillis (united states)
    date: Monday 17th July 2017
    text: Unbelievably, I actually have the original cardboard box for a TRS 80 model 4P that I recovered from my folks attic where it sat undisturbed for decades. The internal packing material is long gone, but the box itself is in very good shape. I was going to flatten it and recycle it unless someone wants it. Any takers?
  - author: Marcus N. (Germany)
    date: Monday 12th December 2016
    text: Dear Mr. Bryant, do you still have these manuals and Softwaredisks? I''m about to buy a TRS-80 4p with nothing except the defective machine... I would be so happy if you could send it over here to Germany by Mail postage - of course all on my cost :-)
  - author: Dean Notarnicola (NJ, USA)
    date: Tuesday 10th November 2015
    text: 'Harry and John: Do you still have those Model 4P computers?'
  - author: Harry Bryant (United States)
    date: Saturday 29th August 2015
    text: I have a TRS80 4P and assoiated manuals and software. I''d gladly donate it to a hobbiest/museum for the cost of shipment.
  - author: Chuck Rose
    date: Thursday 15th January 2015
    text: My model 4P had double sided drives just like the 4D. I developed with it mostly in CP/M mode because it had the bigger market compared to the model 4.
  - author: John E Iacono (USA)
    date: Monday 13rd October 2014
    text: I have a 4P that has not been turned on for about 20 years. Also several hundred dsdd floppies, if anyone is interested. We used it in our accounting company for several years.
  - author: Richard
    date: Thursday 10th November 2011
    text: I have this computer but do not have a power cord. Would any power cord work?
  - author: Richard
    date: Thursday 10th November 2011
    text: I have this computer but do not have a power cord. Would any power cord work?
  - author: James (USA)
    date: Saturday 4th June 2011
    text: I am still in possession of the Model 4P that my father purchased for me in 1984. (my junior year of HS.) The unit is still in functional condition, although the floppy''s are getting worn out. Anyone know where I could find replacement disks for it ??
  - author: Charles Rose (Maine, USA)
    date: Wednesday 21st October 2009
    text: Ahhh yes, the TRS-80 4P. I had one of these machines as my main computer in the mid/late 80''s. I used it to keep the books for my freelance software company as well as developed some software for it (mainly a Video renting system) in Model III mode. I have not-so-fond memeories of hauling this thing through various airports to make connecting flights. I think the only thing that made it portable was the handle in the case lol. It was seriously a very heavy ''portable'' machine.
  - author: Andy (Washington)
    date: Tuesday 20th June 2006
    text: Well, went to my local Goodwill today and bought one of these babys for a smokin price of 5 bucks! Anyone interested in snaging this?
  related:
  - /museum/radionic-model-r1001
  - /museum/sysdata-eletronica-jr
  - /museum/tandy-radio-shack-trs-80-model-12
  - /museum/tandy-radio-shack-trs-80-model-16
  - /museum/tandy-radio-shack-trs-80-model-4
  - /museum/tandy-radio-shack-trs-80-model-i
  - /museum/tandy-radio-shack-trs-80-model-ii
  - /museum/tandy-radio-shack-trs-80-model-iii
  oc_id: 1083
  source:
    url: https://web.archive.org/web/20230608220843/http://www.old-computers.com/museum/computer.asp?c=1083
    date: '2023-06-08'
---

The Model 4P was the transportable version of the [Model 4](/museum/tandy-radio-shack-trs-80-model-4/).

Apart from the case and display sizes, technical features were almost identical to the Model 4's. The dual half-sized floppy drives were still single-sided versions but the keyboard, which slided underneath the computer, was far better than the one of the desktop version.

The external floppy drive connector was removed, as well as the Model 3 ROM, but a ROM image could be loaded from diskette to run Model 3 programs. An optional 300-baud modem could be also installed into the machine.

Very late models had double-sided TEAC drives.

---

Further information from **Greg Trotter**\
I used a Model 4P for many years. It was pretty much identical to the Model 4 in functionality, except for:\
\- Portability, of course\
\- No Model III ROM (but you could load an image of the ROM into the RAM and reboot, giving perfect compatibility)\
\- It did have a modem card slot, except that the card edge provided power only; the outward face of the card had a short DC-25 serial cable, just long enough to get to the serial port of the 4P.\
\- There was no cassette interface on the 4P.\
\- The keyboard was indeed superior; I liked it better because it was corded and could be moved to any angle.

Of course, portable just meant "easier to transport." The entire unit weighed about 28 pounds, if I remember correctly. I lugged it through airports, and it fit quite comfortably in the overhead bin.