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---
title: Tandy Radio Shack TRS 80 MODEL I
categories:
- Computers
types:
- Home Computer
origins:
- U.S.A.
years:
- '1977'
cpus:
- Zilog Z80
params:
name: TRS 80 MODEL I
image: /media/museum/photos/tandy_model1_system_s1.jpg
company: /companies/tandy-radio-shack
company_name: Tandy Radio Shack
specs:
- label: NAME
value: TRS 80 MODEL I
- label: MANUFACTURER
value: Tandy Radio Shack
- label: TYPE
value: Home Computer
- label: ORIGIN
value: U.S.A.
- label: YEAR
value: '1977'
- label: BUILT IN LANGUAGE
value: |-
Basic Level 1 (4k ROM models)\
Basic Level II (12k ROM models)
- label: KEYBOARD
value: Full-stroke keyboard, 53 Keys, optional numeric keypad
- label: CPU
value: Zilog Z80
- label: SPEED
value: 1.77 MHz
- label: RAM
value: 4 kb / 16 kb depending on models (up to 48 kb)
- label: VRAM
value: 1 kb
- label: ROM
value: 4 kb (Basic Level 1) or 12kb (Basic Level 2)
- label: TEXT MODES
value: 32 x 16, 64 x 16
- label: GRAPHIC MODES
value: 128 x 48
- label: COLORS
value: monochrome
- label: SOUND
value: None
- label: I/O PORTS
value: Monitor, cassette interface, expansion port
- label: OS
value: TRS DOS - NEW DOS
- label: PRICE
value: |-
#26-1003 : Model I, Level I, 16K = 700 (France,81)\
#26-1004 : Model I, Level II, 4K = 640 r (France,81)\
#26-1006 : Model I, Level II, 16K = $1099
tabs:
- photos
- adverts
- hardware
- software
- emulators
- links
forum_thread: 406
photos:
- title: LEVEL 1 MODEL
subtitle: ''
text: Basic version of the first Level 1 model with its power supply unit and tape recorder.
image: /media/museum/photos/tandy_model1_systeml1_s1.jpg
- title: BOOT-UP SREEN
subtitle: ''
text: ''
image: /media/museum/photos/tandy_model1_bootscreen_s1.jpg
- title: TOP VIEW
subtitle: ''
text: Model II connected to the expansion unit located below the monitor.
image: /media/museum/photos/tandy_model1_topview_s1.jpg
- title: BOTH SIDES
subtitle: ''
text: ''
image: /media/museum/photos/tandy_model1_2sides_s1.jpg
- title: REAR SIDE
subtitle: ''
text: |-
From left to right:\
• Tape recorder DIN socket\
• Monitor DIN socket\
• Power trasformer DIN socket\
• Power switch\
• Expansion connector.
image: /media/museum/photos/tandy_model1_rearside_s1.jpg
- title: COMPLETE SYSTEM
subtitle: ''
text: |-
Very complete (and expensive at the time!) version including the expansion unit, two floppy drive units, a 5 MB hard disk unit and the Line Printer 1 dot matrix printer.
Special thanks to **Georges Chapuzot** who donated us this system.
image: /media/museum/photos/tandy_model1_completesystem_s1.jpg
- title: 'COMPLETE SYSTEM #2'
subtitle: ''
text: TRS 80 Model 1 + expansion unit + voice synthesizer + tape recorder + disk drives + printer
image: /media/museum/photos/tandy_trs80-model1_complete_1.jpg
- title: LEVEL I & LEVEL II
subtitle: ''
text: Externally, the only difference is the numeric keypad added to the Level II.
image: /media/museum/photos/tandy_model1_systeml1l2_s1.jpg
- title: OPENED
subtitle: ''
text: The keyboard circuit is supported by the main board which components face the bottom of the case. This model was a Level I version converted into a level II. The BASIC ROMs are located below the numeric keypad and connected to the ROM socket of the main board by a flat cable.
image: /media/museum/photos/tandy_model1_inside_s1.jpg
- title: MAINBOARD
subtitle: ''
text: |-
A true Level II version.
**(1)** Reset switch\
**(2)** Power regulators\
**(3)** 16 KB RAM chips (8 x 4116)\
**(4)** Keyboard cable\
**(5)** Z80 CPU, here a Mostek version\
**(6)** 8K + 4K ROM chips\
**(7)** DIN sockets ans power switch.
image: /media/museum/photos/tandy_model1_mainboard_s1.jpg
- title: THE BOX
subtitle: ''
text: The box holds a complete Level 1 4K system.
image: /media/museum/photos/tandy_model1_box_s1.jpg
- title: THE VERY FIRST VERSION
subtitle: ''
text: The TRS-80 during one of its first public show, in October, 1977, with F.D. unit prototypes.
image: /media/museum/photos/tandy_model1_first_1.jpg
- title: PROMOTIONAL PICTURE
subtitle: ''
text: ''
image: /media/museum/photos/tandy-trs80m1_prm-pic.jpg
adverts:
- title: FIRST U.S. ADVERT (1977)
subtitle: ''
text: ''
image: /media/museum/pubs/tandy_model1_pub_4.jpg
- title: U.S. ADVERT (1978)
subtitle: ''
text: Thanks to Orion Young for this picture
image: /media/museum/pubs/tandy_model1_pub_1.jpg
- title: U.S. ADVERT (1979)
subtitle: ''
text: ''
image: /media/museum/pubs/tandy_model1_pub_2.jpg
- title: MICROSOFT ADVERT (1979)
subtitle: ''
text: |-
Advert said:
No one knows better than Microsoft how to increase your TRS-80 BASIC's power. Microsoft created the TRS-80 Level ll and Disk BASIC plus the industry standard Microsoft BASIC...
...Microsoft Level lll BASIC is an enhancement to the Level ll. It contains all Disk BASIC features not already in Level ll and it adds six new Level lll exclusives...\
...Advanced graphics is Level lll's most exciting addition to the TRS-80 - and it's exclusive. Draw a line, outline or solid box by specifying just two points, then save it and put it back with BASIC statement. You'll find yourself writing more programs with charts, graphs and even animation...
image: /media/museum/pubs/tandy_model1_pub_3.jpg
- title: U.S. ADVERT (1980)
subtitle: ''
text: In september 1980, over 200,000 Model 1 were sold, more than 50,000 units per month since the computer was launched.
image: /media/museum/pubs/tandy_model1_pub_5.jpg
- title: FRENCH AD (JAN. 1980)
subtitle: ''
text: ''
image: /media/museum/pubs/tandy_trs80-model1_pub_computercenter_1.jpg
- title: FRENCH ADVERT (1980)
subtitle: ''
text: Dated december 1980
image: /media/museum/pubs/tandy_trs80-model1_pub_grande-ouverture.gif
- title: TANDY BROCHURE COVER
subtitle: ''
text: Cover of a Tandy catalogue.
image: /media/museum/pubs/tandy_model1_pub_6.jpg
hardware:
- title: VOXBOX
subtitle: Serial# 26-1181
text: |-
The VoxBox is a voice recognition device with a CB-style microphone attached. You have to push-to-talk, and though it can only recognize a few words at a time, it is fun to play with. You can program the TRS-80 Model 1 (level II) so it can react to specific words.
It cost 925fr (France, 1981)
image: /media/museum/hardware/tandy_trs80-m1_voxbox_1.jpg
- title: MUSIC SYNTHESIZER
subtitle: ''
text: It has a left and right audio output.
image: /media/museum/hardware/tandy_trs80_music-synthesizer_1.jpg
- title: VOICE SYNTHESIZER
subtitle: Serial# 26-1180
text: |-
This is a real voice synthesizer with built-in speaker. Is sounds too cool with its robotic voice. Can be used with Level I or II Basic but the TRS-80 must have at least 16k RAM.
It cost 2695fr (France, 1981)
image: /media/museum/hardware/tandy_trs80-m1_voice-synth_1.jpg
- title: VOICE SYNTHESIZER
subtitle: Another picture
text: ''
image: /media/museum/hardware/tandy_trs80_voice-synthesizer_2.jpg
- title: 'DUAL MINIDISK UNIT #1'
subtitle: 'Ref #26-1160'
text: |-
Up to 4 minidisks could be attached. They used 5''1/4 disks. Minidisk 1 had a capacity of 55kb and additional ones 89kb, or 160 KB for dual density version.
#26-1160 : Minidisk 1 cost 470 Euros (France, 81), $699.00 (USA)\
#26-1161 : Additional minidisks cost 426 Euros (France, 81)
image: /media/museum/hardware/tandy_model1_fdunits_s1.jpg
- title: 'DUAL MINIDISK UNIT #2'
subtitle: Inside
text: The floppy drive was a Tandon single side, single density model.
image: /media/museum/hardware/tandy_model1_insidefdd_s1.jpg
- title: '5 MB HARD DISK UNIT #1'
subtitle: ''
text: ''
image: /media/museum/hardware/tandy_model1_hdunit_s1.jpg
- title: '5 MB HARD DISK UNIT #2'
subtitle: Inside
text: The unit used a Tandon 5.25" HDD. Up to 4 similar HDD could be connected to this unit.
image: /media/museum/hardware/tandy_model1_insidehdunit_s1.jpg
- title: 'EXPANSION UNIT #1'
subtitle: Ref. 26-114x
text: |-
Most of the serious TRS-80 users bought this expansion unit which gave 16 or 32 KB more RAM. The TRS-80 thus reached a wooping 48 KB RAM
It also offered a provision for using two cassette tape units, a Parallel printer port, the floppy disk controller (single then dual density), a serial port and a real-time clock interrupt that was used by various DOS systems for time keeping functions.\
French Prices (1981):\
26-1140 : Expansion unit alone = 320 Euros\
26-1141 : ... with 16k RAM = 452 Euros\
26-1142 : ... with 32k RAM = 585 Euros\
26-1102 : 16k RAM kit = 135 Euros\
US prices:\
26-1140 : Expansion unit alone = $449\
26-1102 : 16k RAM kit = $189
image: /media/museum/hardware/tandy_model1_expansionbox_s1.jpg
- title: 'EXPANSION BOX #2'
subtitle: Inside
text: This version holds 32 KB RAM and an add-on card for dual density floppy disk drives. Provision was made for the main unit's AC adaptor.
image: /media/museum/hardware/tandy_model1_insideexpbox_s1.jpg
- title: TAPE RECORDER
subtitle: Ref# 14-841
text: The tape recorder was a standard version also sold separately in Tandy shops.
image: /media/museum/hardware/tandy_model1_taperecorder_s2.jpg
- title: NUMERIC KEYPAD
subtitle: Serial# 26-1031 / 26-1103
text: The numeric keypad was mounted on 16k models, but could also be added to 4k models (Level I or II) in place of the "TRS-80" label...
image: /media/museum/hardware/tandy_trs80-m1_keypad_1.jpg
- title: RS232C CARD
subtitle: Serial# 26-1145
text: |-
This RS232c card is meant to be mounted into the expansion unit and enables the TRS-80 to communicate with various devices such as a modem.
It cost 729fr (France, 1981)
image: /media/museum/hardware/tandy_trs80-m1_rs232c-card_1.jpg
- title: RADIO SHACK MODEMS
subtitle: ''
text: |-
**(1) Direct-Connect Modem 1** Full-duplex modem. 300 baud Bell 103J compatible. Did not need an RS-232 board in TRS-Model 1 computers.\
**(2) Direct-Connect Modem 2** Same as Modem 1 + Built-in 6805 microprocessor. 25 chars. register to store commands and parameters for automatic dialing and operations.\
**(3) Telephone Interface 2** Used to transfer data through a telephone handset. 300 baud, full or half duplex operations.
image: /media/museum/hardware/tandy_model1_modems_1.jpg
- title: MODEM 1B
subtitle: ''
text: ''
image: /media/museum/hardware/tabdy_trs80_modem1_1.jpg
- title: ACOUSTIC MODEM
subtitle: ''
text: ''
image: /media/museum/hardware/tandy_trs80-m1_acoustic-modem_1.jpg
- title: LYNX TELEPHONE COUPLER
subtitle: ''
text: ''
image: /media/museum/hardware/tandy_model1_lynxpub_1.jpg
- 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: TRS80 PRINTER CONTROLLER
subtitle: ''
text: ''
image: /media/museum/hardware/tandy_trs80_printer-controller_1.jpg
- title: DMP-200
subtitle: ''
text: 80-column, 100 cps dot matrix printer.
image: /media/museum/hardware/tandy_model3_dmp200_s1.jpg
- title: QUICK PRINTER II
subtitle: Serial# 26-1155
text: |-
Ideal affordable printer for TRS-80 users (that's what the ad says...). It uses special paper-rolls (6cm large). Can print 16 or 32 c/line.
It cost 1495fr in 1981 (France).
image: /media/museum/hardware/tandy_trs80-m1_quick-printer-2_1.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: PLOTTER
subtitle: Serial# 26-1190
text: |-
Multidirectionnal printer/plotter.\
10 c/s print rate.\
Printing wide size : 19cm
It cost 6250fr (France) in 1981.
image: /media/museum/hardware/tandy_trs80-m1_plotter_1.jpg
- title: GRAPHIC PLOTTER
subtitle: 4-pen mini printer-plotter
text: ''
image: /media/museum/hardware/tandy_trs80_graphic-plotter_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 Computer Emulator Pages
url: http://discover-net.net/~dmkeil/
platform: MS DOS
text: This program emulates a complete TRS-80
- 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: Jeff Vavasour's TRS-80 EMULATION Page
url: http://www.vavasour.ca/jeff/trs80.html#model1
platform: MS DOS
text: This emulator simulates a 48K TRS-80 Model I with 4 disk drives, printer, RS-232 board, and cassette drive.
- 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: THE TRSF-80 HOME PAGE
url: http://members.aol.com/trsf80/
platform: MS DOS
text: The TRSF-80 emulator is designed to emulate a TRS-80 Model I computer on a DOS-based Intel x86 platform
- 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: Yves Lempereur's TRS-80 Emulator for Mac OS
url: http://www.vcnet.com/~skyrider/trs80.html
platform: Apple
text: TRS-80 emulator for MAC which simulates the TRS-80 emulator simulates a TRS-80 Model I with an Expansion Interface, two 5" floppy drives and 48K of RAM
- 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
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-4p
- /museum/tandy-radio-shack-trs-80-model-ii
- /museum/tandy-radio-shack-trs-80-model-iii
software:
- /software/galaxy-invasion
oc_id: 409
source:
url: https://web.archive.org/web/20230602050749/http://www.old-computers.com/museum/computer.asp?c=409
date: '2023-06-02'
---
The Tandy TRS 80 model 1 was the first member of one of the most famous computer family. It was one of the first home computer and was launched at the same time as famous computers like the [Apple II](/museum/apple-ii/) or the [Commodore PET](/museum/commodore-pet-2001/). Beside, Tandy competitors nicknamed was "Trash-80".
The TRS-80 was developed was developed within the Radio Shack engeneering group, based upon several processor chips, SC/MP, PACE, 8008, 8080 and finally the Z80.
It used a black & white TV set, made by RCA, without tuner as monitor. The earlier models use a poor basic called Basic Level 1 (the Basic and the OS fit in the 4 KB ROM!). It was replaced later with the Basic Level 2 which needed a 12 KB ROM.
To offset its poor characteristics, Tandy developed a device called Expansion Interface which brings a lot of new features : additional 16 or 32kb RAM, two tape unit connectors, a printer port, a floppy disk controller, a serial port and a real time clock.
Tandy did as well 5, 10 and 15 MB hard drives. The case for them is about the size of a small PC tower. It's possible to fit 2 drives into each case. They were compatible with all TRS-80 versions.
When it was connected to a floppy disk unit, the TRS-80 uses the TRS DOS operating system, it was pretty bugged and most of the TRS-80 users prefered NEW DOS, it was an operating system done by a third-party company called Apparat. This OS was the real TRS-80 operating system.
LS-DOS was also an excellent DOS, superior to NEW DOS for most users. Interestingly, Microsoft's MS-DOS became more and more like LS-DOS each time it was updated, although never as good. LS-DOS was finally adopted by Tandy as the official DOS for the [Model 4](/museum/tandy-radio-shack-trs-80-model-4/).
Documentation for all the TRS machines was superb. Even Microsoft provided documentation for its BASIC interpreter listing all the machine calls. You could use these calls when programming with either machine code or BASIC.
The Model I was followed by the [TRS 80 model II](/museum/tandy-radio-shack-trs-80-model-ii/) (a business computer) and [model III](/museum/tandy-radio-shack-trs-80-model-iii/) which had almost the same characteristics as the model I.
---
**Contributors :** Donald French, Paul D Moore
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