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

title, categories, types, origins, years, cpus, params

title	categories	types	origins	years	cpus	params
Tandy Radio Shack TRS 80 MODEL 4	Computers	Professional Computer	U.S.A.	1983	Zilog Z80	name image company company_name specs tabs forum_thread photos adverts hardware emulators links related oc_id source TRS 80 MODEL 4 /media/museum/photos/tandy_model4_running_s1.jpg /companies/tandy-radio-shack Tandy Radio Shack label value NAME TRS 80 MODEL 4 label value MANUFACTURER Tandy Radio Shack label value TYPE Professional Computer label value ORIGIN U.S.A. label value YEAR 1983 label value BUILT IN LANGUAGE None label value KEYBOARD Typewriter style 83 keys with numeric keypad label value CPU Zilog Z80 label value SPEED 4 MHz label value RAM 64 KB (up to 128 KB) label value ROM 14 KB label value TEXT MODES 64 x 16 / 32 x 16 / 64 x 40 / 80 x 24 label value GRAPHIC MODES None label value COLORS Monochrome green phosphore label value SOUND Built-in speaker label value SIZE / WEIGHT 47.5 (W) x 52 (D) x 31 (H) cm label value I/O PORTS Tape (500 or 1500 bauds), Centronics, I/O ports compatible with Model III, Serial (4D) label value BUILT IN MEDIA One or Two 5.25'' disk-drives label value OS TRSDOS 6.0 or 1.3, LDOS, CP/M label value POWER SUPPLY Built-in power supply unit label value PRICE From $1990. In later years the price came down to about $1000\ By 1990 the Model 4D was being closed out at $599 photos adverts hardware emulators links 254 title subtitle text image FIRST VERSION Two Model 4 versions were released. One can recognize them at the surface from the different arrangement of the arrow keys. /media/museum/photos/tandy_model4_system_s1.jpg title subtitle text image SECOND VERSION The second version had an improved gate-array mainboard and a new location for the serial port.\ The arrow keys are now clustered to the right of the keyboard.\ This version features a second 3.5" DS DD 720 KB floppy drive (Tandy option). /media/museum/photos/tandy_model4_systemus_s1.jpg title subtitle text image MODEL 4 PLATE /media/museum/photos/tandy_model4_plate_s1.jpg title subtitle text image BOTH KEYBOARD VERSIONS /media/museum/photos/tandy_model4_keyboards_s1.jpg title subtitle text image KEYBOARD CLOSE-UP The red button is the Reset switch /media/museum/photos/tandy_model4_keybcloseup_s1.jpg title subtitle text image SIDE VIEW /media/museum/photos/tandy_model4_sideview_s1.jpg title subtitle text image TOP VIEW /media/museum/photos/tandy_model4_topview_s1.jpg title subtitle text image FRONT PANEL Both FDD drives were Tandon Single-sided, single density models. /media/museum/photos/tandy_model4_fdds_s1.jpg title subtitle text image BOTTOM SIDE **(1)** Parallel printer connector\ **(2)** Serial connector\ **(3)** Expansion port connector\ **(4)** Video adjustment\ **(5)** Tape recorder DIN socket /media/museum/photos/tandy_model4_bottomview_s1.jpg title subtitle text image INSIDE #1 The mainboard is mounted vertically at the back. /media/museum/photos/tandy_model4_inside_s1.jpg title subtitle text image INSIDE #2 The top cover holds the CRT and its electronics. A fan has been added on top of the CRT. /media/museum/photos/tandy_model4_topcover_s1.jpg title subtitle text image MAINBOARD, 1ST VERSION The fist mainboard version used only standard chips. It had 64 KB of RAM. Provision was made for a second 64 KB RAM bank.\ The separate floppy-disk controller card was located behind the mainboard as well as a smal sound generator circuit. /media/museum/photos/tandy_model4_mainboard_s2.jpg title subtitle text image MAINBOARD, 2ND VERSION The second "gate array" version included the floppy-disk controller, the sound generator and buzzer and a second serial port. **(1)** Power connector\ **(2)** Video connector\ **(3)** Tape recorder connector\ **(4)** 128 KB RAM chips (16x4164 equivalents)\ **(5)** WDC1865 UART, serial port controller\ **(6)** WD1773 floppy-disk controller\ **(7)** BIOS ROMs\ **(8)** Z80 CPU socket. In this machine, the CPU chip was replaced by a RAM expansion piggy-back card Other chips were custom made for Tandy and had unknown part numbers. /media/museum/photos/tandy_model4_mainboard_s1.jpg title subtitle text image RAM CARD This RAM card is inserted on the Z80 CPU socket and provides up to 1 MB of extra RAM (2 x 512 KB DIP modules) used as a virtual floppy-disk drive. /media/museum/photos/tandy_model4_ramcard_s1.jpg title subtitle text image US ADVERT, NOV. 1985 /media/museum/pubs/tandy_model4d_pub_s1.jpg title subtitle text image REMOTE UNIT ACTIVE Serial# 26-1210 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) /media/museum/hardware/tandy_trs80-m1_remote-unit-active.jpg title subtitle text image NETWORK II BOX p/n 26-1211 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. /media/museum/hardware/tandy_network2_s1.jpg title subtitle text image DMP-200 80-column, 100 cps dot matrix printer. /media/museum/hardware/tandy_model3_dmp200_s1.jpg title subtitle text image DAISY WHEEL PRINTER II Serial# 26-1158 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) /media/museum/hardware/tandy_trs80-m1_daisy-wheel-printer-2_1.jpg title subtitle text image LINE PRINTER I Ref# 26-7017 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). /media/museum/hardware/tandy_model1_lineprinter1_s1.jpg title subtitle text image LINE PRINTER III Serial# 26-1156 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). /media/museum/hardware/tandy_trs80-m1_line-printer-3_1.jpg title subtitle text image LINE PRINTER VI Serial# 26-1166 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). /media/museum/hardware/tandy_trs80-m1_line-printer-6_1.jpg title subtitle text image TP-10 THERMAL PRINTER Box /media/museum/hardware/tandy_trs80_tp-10_thermal-printer_box.jpg title subtitle text image EXATRON Stringy Floppy drive 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 /media/museum/hardware/tandy_model3_exatronwafer_s1.jpg title url platform text David Keil's TRS-80 Model III/4/4P Emulator Page http://discover-net.net/~dmkeil/trs80/model4.htm MS DOS This program emulates a complete TRS-80 title url platform text Matthew Reed's TRS-80 Emulator Web Site http://www.arrowweb.com/mkr/ MS DOS This page offers shareware versions of a TRS-80 Model 4 emulator and a TRS-80 Model 1-2 emulator title url platform text TRS-80 Model III/4 Emulator http://www.vavasour.ca/jeff/trs80.html#model4 MS DOS This TRS-80 Model III/4 Emulator is a commercial product title url platform text Model 4 Emulator http://www.arrowweb.com/mkr/ Windows title url platform text XTRS for Unix / X http://www.research.digital.com/SRC/personal/Tim_Mann/trs80.html Unix / Linux title url platform text xtrs: TRS-80 Model I/III/4 Emulator for Unix http://www.tim-mann.org/xtrs.html Unix / Linux xtrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for Unix and the X Window System title url platform text TRS-80 Level I BASIC in a browser http://www.vavasour.ca/jeff/trs80.html#simulator Other platform With this Java emulator, you'll be able to write a BASIC program directly in your browser! title url platform text Ira Goldklang's TRS-80 Revived Pages http://www.trs-80.com/trs80-e.htm Multiplatform A complete list of TRS-80 emulators for various platforms ! title url platform text MESS http://www.mess.org Multiplatform MESS emulator also emulates a TRS-80 systems title url text 8bit-micro.com - Online TRS-80 Computer Magazine HTTP://WWW.8BIT-MICRO.COM Online Magazine dedicated to the TRS-80 and other Vintage - Monthly Issues title url text David's TRS-80 Page http://freespace.virgin.net/david.sampson/ title url text Ira Goldklang's TRS-80 Revived Pages http://www.trs-80.com/ Lof of infos about all TRS-80 computers title url text Java TRS-80 Model 1 BASIC Interpreter http://ganley.org/software/trs80.html title url text Mike's Personal Computer Museum http://personal.nbnet.nb.ca/mclays/trsmod1.html Level 1 & 2 Basic summaries, Tandy time-lines, price-list, etc ... ! title url text RadioShackCatalogs.com http://www.RadioShackCatalogs.com Here, you can actually/virtually flip-through the pages to view the content of every RadioShack catalog! title url text The TRS-80 Home Page http://www.kjsl.com/trs80 Full of infos title url text Tim Mann's TRS-80 Page http://www.tim-mann.org/trs80.html Infos, tools and home of xtrs, a Model I/III/4 emulator for Unix title url text Web Wiz CAPTCHA http://www.webwizcaptcha.com Discussion about Tandy computers /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-4p /museum/tandy-radio-shack-trs-80-model-i /museum/tandy-radio-shack-trs-80-model-ii /museum/tandy-radio-shack-trs-80-model-iii 244 url date https://web.archive.org/web/20230608082555/http://www.old-computers.com/museum/computer.asp?c=244 2023-06-08

The TRS-80 model 4 (ref 26-1068/69) was one of the last models of the TRS-80 series (and perhaps the less known). It ran at 4 MHz and displayed 80 columns x 24 lines in Model 4 mode, but was fully compatible with the TRS-80 model 3 and in Model 3 mode actually displayed 64x16 and ran at the Model 3's 2 MHz.

It had 64 or 128 KB RAM, the 64 upper KB being used as a ram disk. It had one or two 5.25" floppy disk (184 KB each) and ran under TRSDOS 6.0 or 1.3, LDOS or CP/M.

A transformation kit "TRS80 model III -> model IV" was available.

The Model 4 was followed by the Model 4D (ref. 26-1070). The only difference being double sided drives -384 KB, instead of single sided drives.

A portable version of the Model IV called Model 4P (ref. 26-1080) was also marketed few time after.

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Dwight Briney specifies:
A graphics adapter was also available for the Radio Shack TRS-80 Model IV in 1983. It came with a graphics programming language (BASICG). I used BASICG to program a basketball shot chart program that was used for a few seasons until I finally converted it to the IBM compatible Hercules graphics adaptor that had higher resolution.
It all seems pretty primitive now, but it worked great at the time.