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*** TRS-80 Model 2000 FAQ ***
Version 2.3 (01/15/2005)
Version 1.0 (05/17/1998)
Jeff Hellige (
This is the second major version of a FAQ for the TRS-80 Model 2000
microcomputer. It is far from complete and will be added to as I gain more
information with which to fill out different sections.
1) Purpose
2) Disclaimer
3) What is the TRS-80 Model 2000?
4) What made the Model 2000 so much more advanced than the IBM PC-XT?
5) If the machine was so advanced, why wasn't it successful?
6) What about hardware?
7) What monitors were available for the Model 2000?
8) If the CM-1 is so rare, are there other color monitors one can use?
9) Can a dual-floppy Model 2000 be upgraded to a Model 2000HD?
10) What connections were made between the two power supplies?
11) What is the external hard disk unit?
12) What is the clock/mouse board?
13) What about the floor stand Tandy sold for the Model 2000?
14) Can the 720k drive in the Model 2000 read/write 360k floppies?
15) Can a 1.2meg floppy on my PC read the Model 2000's 720k disks?
16) Can I put a 720k 3-1/2" DSDD drive in my Model 2000?
17) What can I use if I can't find the Tandy Digi-Mouse?
18) What is the DCS?
19) What are the details concerning the Model 2000's serial ports?
20) What is the serial expansion board?
21) How can I take a 128k RAM expansion board to 256k?
22) What is the 'International' keyboard?
23) What is the TV/Joystick option board?
24) Where's the socket for the 8087 co-processor?
25) What are the specifications for the Intel 80186 cpu?
26) What are the pinouts for the Model 2000's various ports?
27) What operating systems could the Model 2000 run?
28) What software was made for the Model 2000?
29) Can you run IBM-compatible software on the Model 2000?
30) Is it possible to get 'online' with a Model 2000?
31) How can I run Infocom text adventures on the Model 2000?
32) Can I run Microsoft Windows on the Model 2000?
33) What are the 'MAI/Basic Four' programs?
34) Are there any books available on the Model 2000?
35) What 'Tech Bulletins' were sent out by Tandy?
36) Where can I get support for this machine?
37) What is 'Envision Designs'?
38) What is 'Microlink Technology'?
39) Future plans for this FAQ
*** - To be completed in the next version of this FAQ
1) Purpose:
The purpose of this FAQ (Frequently Asked Questions) file is to provide
a single repository for general information regarding the TRS-80 Model 2000
and 2000HD microcomputers produced by Tandy Corp. Though sometimes also
referred to as the Tandy 2000 or T2K, for the purposes of this FAQ, all
references to the machine, including the 2000HD, will be 'Model 2000'. The
latest version of this FAQ may be found at:
All additions or corrections can be submitted to the author, Jeff
Hellige, at:
Special thanks to:
- Frank Durda for contributing new info concerning the Model 2000's
production and the existence of Model 2000 Xenix
- Dennis Smith for providing info on the external hard disk unit and
the serial expansion board.
- Roy Soltoff for providing lots of additional documentation
- Michael Webb for creating the archive
- Jim Atchison for providing additional software information
- Axel Harten for the copy of the German print advertisement
2) Disclaimer:
All information contained in this FAQ is provided for informational
purposes only, to those people interested in the TRS-80 Model 2000 & 2000HD
microcomputer, it's history, and it's continued use. This FAQ may be printed
and posted elsewhere as long as it is done so in it's entirety and not
modified. All hardware & software mentioned are property of the respective
copyright owners. When known, original list prices are shown for hardware
and software for the purpose of historical interest and perspective only.
All text describing a hardware modification are to be followed at the risk
of the reader, as they have not necessarily been tried by the author.
3) What is the TRS-80 Model 2000?
The TRS-80 Model 2000 was Tandy's first try at marketing a MS-DOS based
machine. It was superior to the IBM PC-XT in every way and even cost less
as a bonus. It was manufactured between November 1983 and June 1984, though
there was enough inventory onhand to continue selling them well into 1986.
At one point, there were so many Model 2000's stacked in Tandy warehouses
and factories that Tandy 'sold' 7500 of them to Radio Shack Computer Centers
to be used as daily report and Point-of-sale systems. Finally in 1989 Tandy
sold the remaining machines off for next to nothing in one big sale. The
2000HD was the Model 2000 shipped with a Tandon 10meg MFM hard disk
installed. The machines used in Radio Shack stores as Point-of-sale systems
tended to be fitted with the external hard disk unit. The Model 2000 was
housed in a stylish white case with black drive bezels with power and reset
switches recessed in the front panel near the TRS-80 emblem.
a) TRS-80 Model 2000 (dual floppy) - #26-5103
b) TRS-80 Model 2000HD (10meg HD, single floppy) - #26-5104
The following are the Model 2000's specifications as taken directly from
Tandy FaxBack document# 1941:
Dimensions: 19 x 16 x 6 Weight: 26.5 lbs.
Processor: 80186 CPU Speed: 8 MHz
FCC Class: A, UL Listed Wait States: N/A
Add. Device Exp: N/A
# of Slots: 4 (96-Pin Euroconnector) Std. Memory: 256K
MTBF: N/A Max. Memory: 768K
Op. Sys: 2000 MS-DOS Only *Not PC Compatible*
Video: Built-in Mono Power Supply: 45 to 135 VAC,
Optional Color 60 Hz, 136 Watts
Heat Output: N/A Keyboard: 90-Key Sculptured
Std. Ports: Math Co.: 8087 8 MHz Intel (Opt)
Monochrome Video-(8 Pin Din) Floppy: 720K 5.25" DS 80 Track
Serial-(DB-25 F) Environment: Operating: 55 to 96F
Centronics Parallel-(34 Pin Header) Storage:-40 to 160 F
Humidity: N/A
CURRENT BIOS ROM Version: 02.00.00 Utilities Version: N/A
4) What made the Model 2000 so much more advanced than the IBM PC-XT?
a) CPU: 8mhz Intel 80186 when the PC-XT was running an 8088 at 4.77mhz.
The 80186 is a 16bit CPU.
b) Floppy: Mitsubishi 720k DSQD (80 track, Quad Density) floppies vice
the 360k DSDD floppies used by the PC-XT.
c) Graphics: 8 colors at 640x400 when CGA was 4 colors at 320x200 and
640x200 in black/white.
d) Price: $2999 vice $3658 for a similarly equipped IBM PC-XT, as of
Model 2000: 128k RAM, 80186 at 8mhz, dual 720k floppy drives, monochrome
graphics with VM-1 monitor, RS-232 (built-in) & parallel
printer ports (built-in), MS-DOS 2.0
IBM PC-XT: 128k RAM, 8088 at 4.77mhz, dual 320k floppy drives, mono
display (text only), RS-232 and parallel printer ports,
MS-DOS 2.0.
All of the above combined to make the Model 2000 an excellent business
machine at the time, especially for CAD work. Tandy at one time used the
machine in most of the Radio Shack Computer Center's for in-house databases
and accounting. The Model 2000 was also faster than the early PC-AT, which
used a 6mhz 80286 cpu, and which was announced in August 1984. The PC-AT
listed for $4000 without a hard drive, video card, or monitor, while that
rose to $6700 with the addition of a 20meg hard disk, color card and
5) If the machine was so advanced, why wasn't it successful?
The Model 2000 had one thing against it, and it proved to be a big
problem. Even though it ran MS-DOS the Model 2000 couldn't run most software
made for the PC-XT because of it's hardware differences. This was at a time
when IBM compatibility was becoming a major selling point. Any software
written to access the hardware of the PC-XT directly would fail on the Model
2000. Only software which was either written specifically for the machine
or which accessed the hardware using BIOS calls would run properly.
Programs which deal with graphics are especially problematic.
Unfortunately as well, the Model 2000 started having bugs pop up almost
as soon as it was released. As they were discovered, Tandy released updates
to it's repair centers in the form of 'tech bulletins'. In all, there were
46 of these bulletins sent out, ranging from faulty contact between the
expansion boards and the bus connector due to improper seating, through
the machine randomly resetting itself due to a faulty variable potentiometer
on the power supply. See Section #35 of this FAQ for a listing of these
Tech Bulletins and the dates they were released.
6) What about hardware?
The Model 2000's hardware totally departed from the then-emerging IBM
standard, in an effort to create a superior system and to try to take away
some of the PC-XT's steam and market share. The four expansion slots were
proprietary and few systems made before or since have used either the 80186
cpu or the 720k Quad Density floppy drives (The Altos 586T is one of the few
systems to also use the 720k QD 5-1/4" floppy, though it's drive was made
by Shugart). The signal put out by the Model 2000's graphics board is also
of too high a frequency to be able to be recognized by the standard CGA
monitors of the period. Hence, Tandy released two digital monitors
specifically for the machine. It should be noted that while Tandy used a
fairly standard DB-25 connector for the Model 2000's serial ports, they used
a non-standard 34 pin header connector for the parallel port.
A pricelist dated November 30, 1983 in PDF format is available at the
homepage for this FAQ. This pricelist was sent to Radio Shack stores and
district managers from the District #81 office in Rosslyn, Virginia to act
as a price guide for the then-new Model 2000 and it's various hardware
The following are some of the items available for the Model 2000:
(note: All sold by Tandy except for the three from Envision Designs;
all prices are original list)
a) B/W graphics board - #26-5140 ($449.00)
b) Color graphics option for above - #26-5141 ($199.00)
c) 128k RAM expansion board - #26-5160 ($299.00)
(plugs into mainboard for 256k total)
d) 128k RAM expansion board (plugs into expansion slots) - #26-5161
e) 128k RAM expansion option - #26-5162 ($299.00)
(takes #26-5161 up to 256k using 18-64k x 1 chips)
f) TV/Joystick board - #26-5142 ($249.95)
g) Digi-Mouse/Clock board - #26-5144 ($119.95)
h) Vianet board - #260-1220 or 260-1221
i) DCS (disk cartridge system) Interface Kit - #26-5147
j) GT-2000 graphics tablet (required for VersaCAD) - #??
k) Digi-Mouse - #26-1197 ($99.95)
l) Tandy 2000 DOS Manual (packed with system) - #MT-2605103
m) Tandy 2000 BASIC Manual (packed with system) - #MT-260513-H
n) Parallel printer cable - #26-4401
o) 898k memory upgrade on mainboard from Envision Designs (no known
p) 640k memory expansion board from Envision Designs (no known part#)
q) Hard disk controller with external connector - #AX-9577
r) Hard disk controller without external connector - #AX-9451
s) Hard disk controller (external connector only) - #26-5127
t) Model 2000 hard disk upgrade kit (internal with 10meg HD) - #26-5125
u) Serial expansion board - #26-5164
v) 8087 numeric coprocessor board - #26-5143
w) 8087 numeric coprocessor board from Envision Designs (no known part#)
x) Monitor pedestal for VM-1 - #26-5115 ($89.95)
y) Floor stand - #26-5116 ($145.00)
z) External hard disk unit - #25-1025 ($699.00)
7) What monitors were available for the Model 2000?
a) VM-1: the 12" monochrome monitor by Tandy, part# 26-5111 ($249.00)
b) CM-1: the 14" color monitor by Tandy, part# 26-5112 ($799.00), rare
even when the Model 2000 was a recent machine, and very difficult
to find now. The CM-1 used an included adapter cable to go from it's
EIA 8-pin connector to a DB-9.
Note: Both monitors offer the same 640x400 graphics resolution and
26.4 khz scan frequency, though the text resoultion on the VM-1 was
much higher.
The VM-1 had two cables available as follows:
a) 8-pin DIN to 8-pin DIN (no graphics board installed) - #WA-0422
b) 8-pin DIN to DB-9 (graphics board installed) - #WA-0204
Interestingly, Tandy also released three video cards so that the CM-1
could be used on a regular PC-XT machine. As taken directly from the 'Tandy
1000-series FAQ' by Jeff Hayes <>:
"Tandy made at least three video cards that would permit the CM1 to be
used with an IBM PC. With the Dual Text Display Adapter, catalog number
25-3046, the CM1 displays only text. With the Dual Graphics Display Adapter,
catalog number 25-3047, the CM1 can display CGA-compatible 640x200 graphics,
or 640x400 graphics with special software. With the Enhanced Graphics
Adapter, catalog number 25-4037, the CM1 displays 640x350 EGA graphics. The
VM1, a monochrome monitor for the 2000, works with the same cards. No
non-Tandy card will work with the CM1 or VM1."
8) If the CM-1 is so rare, are there other color monitors one can use?
Most early multisync-type monitors that accept digital input and which
can sync to the Model 2000's 26.4 khz scan frequency should work fine. I
personally have used a NEC Multisync and NEC Multisync GS with this machine.
The graphics adapter utilizes a standard DB-9 video connector.
9) Can a dual-floppy Model 2000 be upgraded to a Model 2000HD?
Tandy sold a hard disk upgrade kit for the dual-floppy Model 2000 which
essentially included everything needed, including a Tandon 10meg drive which
was mounted internally. The Model 2000 hard disk upgrade kit carried part#
26-5125. For the user to do the upgrade themselves required the following:
a) Secondary 38w piggyback power supply, as the main power supply is not
strong enough to handle the additional load. Part# ??
b) Bracket to hold the hard disk between the floppy mounting tower and
the power supply. part# ??
c) MFM hard disk of your choice. Seagate ST-225's work fine for this, as
the 10meg Tandon drives shipped with the 2000HD were quite slow.
d) MFM hard disk controller. There were three major versions of this
made for the Model 2000. The earlier version of the board didn't
include a connector for an external drive, while the later did. These
boards could not support drives daisy chained together. Some users
even used the external connector to feed the ribbon cables back into
the machine to allow two half-height hard disks to be used. This
board must go in the top expansion slot. The third version of the
board seems to have been used mainly by Tandy for machines used in
Radio Shack stores and only had the external connector, with no
provisions for using internal drives.
e) Secondary expansion slot connector for connecting the MFM control and
data cables to the hard disk controller. Connects inline with the top
expansion slot on two stanchions. This is required, as an additional
connector on the expansion card plugs into this, which in turn splits
into the control and data cables for the MFM hard disk. The cables
feed through a cutout in the card cage to the rear of the drive.
If the user bought a hard disk controller with an external connector and
the external hard disk unit, #25-1025, the above items were no longer
required since the external drive had it's own power supply and connecting
cable. Also, Tandy Technical Bulletin #2000:22 states that in order for
the Model 2000 to use the hard disk, one must check the version of the boot
ROMs at U47 and U48. If they are marked 'Boot HD' or 'Boot 103' then they
will work as hard disk boot ROMs. If marked 'Boot 16' then they will have
to be replaced with the following:
U47 MX-5996
U48 MX-6006
10) What connections were made between the two power supplies?
The below information was taken directly from Tandy Technical Bulletin
#2000:22, dated August 14, 1984, outlining the installation of the hard
drive upgrade kit into a Model 2000, #26-5103:
PROCEDURE: Remove top cover from computer. Remove access plate on top of
main power supply. Install hard drive power supply as follows:
1) Hook extra AC connector (blue-brown) from main supply AC harness to
connector next to fuse on hard drive supply.
2) Use one of the green ground wires supplied to run from the spade lug on
hard drive supply to grounding bolt on the inboard side of main supply
3) Connect Red plugs on DC harness supplied with kit to J5 & 6 on hard
drive supply. Mount supply component side down in the hole where the
access cover used to be. Be sure to correctly place grommet on DC harness
through slot in hard drive supply to avoid chaffing.
**** Perform at your own risk ****
11) What is the external hard disk unit?
The external hard disk unit carried Tandy part# 25-1025 and listed
for $699.00. It included the enclosure with built-in power supply and the
same Tandon 10meg hard disk that was used in the Model 2000HD. It was
connected to the external connector on the hard disk controller. It is said
that the hard disk controllers used with some machines in Radio Shack stores
were modified so that the Model 2000 would boot from the external drive.
Also it should be noted that in order for the drive to power on and spin-up,
the computer itself must be powered on. This drive was also sold for use on
other Tandy machines.
12) What is the clock/mouse board?
The clock/mouse board, part# 26-5144 , provided a battery-backed clock
as well as the interface for a digital mouse. This item became available
3/15/84 and allowed a mouse to be used with such programs as VersaCAD and
MS-Windows 1. The digital mouse carried part# 26-1197.
As an interesting side note, the actual circuit card for the clock/mouse
board only used roughly one-half of it's mounting tray. In comparison, most
of the other slide-in expansion cards took up the whole width of the tray
and expansion slot.
13) What about the floor stand Tandy sold for the Model 2000?
The floor stand allowed you to mount the Model 2000 vertically, raising
it off the floor approximately 4-6 inches. The stand was molded plastic, in
a backwards-"L" shape. It was the same color as the Model 2000's case and
the computer mounted to it using four long screws which went through the
stand and into the bottom of the Model 2000. There was a cutout at the rear
for the various ports coming off the computer and the black/silver TRS-80
badge on the front of the Model 2000 rotated to match the computers vertical
position. It made for quite a nice looking unit when used together. It came
with a special extension cable that allowed connection of both the monitor
and keyboard and placement of them up to 8 feet away from the machine. This
extension cable was needed since the keyboard connector at the front of the
machine is covered by the floor stand. One of the connectors on the cable
plugged into the keyboard connector, fed beneathe the machine and came out
the rear of the floor stand, where it merged with the extension cable which
plugged into the monitor port. There were two different versions of the
cable, depending on which monitor port was to be used.
14) Can the 720k drive in the Model 2000 read/write 360k floppies?
Yes, though there were two revisions of the Mitsubishi floppy drive
used in the Model 2000 during it's production and I've heard complaints that
the later version sometimes has problems with DSDD diskettes. Tandy included
a utility with it's DOS version that allowed the user to format standard
360k diskettes. Floppy used is Mitsubishi 4853 (early machines) and 4853-1
(late machines). According to Feb 20, 1988 'Whimper' Mitusbishi 504B312U
may be a good substitute if a floppy drive needs replacement. It is not
known if DSQD floppy drives from other manufacturers, such as Shugart, are
usuable as replacement drives. The utility to format standard 360k disks
and syntax for it's use is:
PCMAKER [drive] [/V]
Note: the /V switch causes it to ask for a volume lable. If you omit
the [drive] designator, PCMAKER formats the current drive. PCMAKER.COM is
available through Tandy Software Replacement as catalog number 700-3602.
15) Can a 1.2meg floppy on my PC read the Model 2000's 720k disks?
Not directly, no. There is a utility, written by David Ogle back in June
of 1987, called Zapmid that will do just that when used in conjunction with
either INTRCPT (author unknown) or 800 II (written by Alberto Pasquale).
Zapmid along with 800 II are available at the home page for this FAQ as file What Zapmid does is change the Media descriptor in the boot
record and the FAT ID on the first FAT to F9h in order for the disks to be
recognized by PC-DOS as 80-track diskettes. INTERCPT and 800 II tell PC-DOS
how to recognize the 80 track format. 800 II is a newer, easier to use
16) Can I put a 720k 3-1/2" DSDD drive in my Model 2000?
Yes, a Panasonic JU-253P, with a jumper unsoldered from R54 and soldered
at R63. This taken from the Jan 23, 1990 issue of the 'Whimper' newsletter.
It says it used this drive because the connector was on the right side (seen
from the front). They also used Panasonic bracket #JU-FDD8200B. It says it
won't work with compdupes or diskcopies with the 720k 5-1/4" drive.
**I've not tried at your own risk**
17) What can I use if I can't find the Tandy Digi-Mouse?
It's possible to take a Tandy part# 25-1040 mouse and rewire the
connector to a 9pin female plug to work in place of the Digi-Mouse. I don't
know the pinout differences though. Taken from the Sept 8, 1989 issue of the
'Whimper'. The pinout for the mouse port is shown in section 26 of this faq.
18) What is the DCS?
DCS stands for Disk Cartridge System. Basically it was a 10meg 8"
cartridge disk system made by Iomega. The drive itself was Tandy #26-1245
and required the use of DCS Interface Kit, #26-5147, which included the
non-booting controller, connecting cable, utilities diskette, and user's
manual. The utilities diskette was Tandy 2000 specific. Iomega later
created a special program so that the Model 2000 could use the 20meg version
though it wasn't widely distributed, so it may be difficult to locate. It
would appear that the utility to use the full capacity of the 20meg version
of the Iomega cartridge system were created by Iomega at the request of the
Tandy 2000 Orphans User Group.
19) What are the details concerning the Model 2000's serial ports?
The serial interface of the Model 2000 relies on the 8251A UART. The
8251A is clocked at 2.00 MHz and is mapped at 0010H - 001FH in the CPU
peripheral address space at even locations only. The 8251A is capable of
up to 19.2K Baud in asynchronous mode.
In asynchronous operation, the baud rate clock is derived from the Intel
8253-5 programmable interval timer. In synchronous mode, the baud rate
clock is generated from the remote device.
The above data was taken from the 'Tandy Model 2000 Service Manual',
including the Intel data sheets contained within it.
20) What is the serial expansion board?
The Serial expansion board, Tandy part# 26-5164, is a 4-port serial
board that plugs into one of the 4 expansion slots on the Model 2000. It
currently is not known what the intended use for this board was or what
software took advantage of it. It is possible to use up to two of these
boards in the Model 2000, giving it a total of 9 serial ports! According
to the board's manual though, there was a modification needed to the
mainboard in order to install the second one. See section 35 for the
Technical Bulletin which details this modification. The manual that shipped
with the board was rather sparce, containing more programming information
than anything else.
21) How can I take a 128k RAM expansion board to 256k?
Tandy sold an option to take the standard #26-5161 RAM expansion
board, which plugged into the expansion slots, to 256k using 18 64k x 1 DRAM
chips. The 256k upgrade for the board carried part# 26-5162 and listed for
22) What is the 'International' keyboard?
The standard keyboard that Tandy shipped with the Model 2000 had 90
keys. The International keyboard had 96 keys, adding numerous international
symbols. It is known that at the least this keyboard was provided to the
German market, as shown in an advertisement dated April 1985, from the
German "Chip" magazine. The photograph clearly shows the international
keyboard with the Model 2000. A JPG of this advertisement is available at
the homepage of this FAQ. It is not known what Tandy part# it carried.
Just like the standard keyboard, it's sticker on the bottom simply states
'TRS-80 Model 2000 Personal Computer Keyboard'. One very noticable
difference between the two are the 5 keys on either side ofthe spacebar,
where there are none on the standard keyboard. On the International
keyboard, there are two keys directly to the left and three keys directly
to the right of the spacebar. Be careful when plugging this up to a
standard Model 2000, as I tried to boot mine with it and in order to get the
machine to boot right again, I had to reboot without the keyboard attached.
Does anyone have any more info on this keyboard and what changes were made
for it's use?
23) What is the TV/Joystick option board?
Supposedly, this item became available on 3/15/84, though I've never
actually seen one or talked to anyone that has. It allowed the connection of
a TV or other non-Model 2000 monitor to the Model 2000, as well as including
a sound generator and support for the use of Color Computer-style joysticks.
24) Where's the socket for the 8087 co-processor?
Unlike a good many other machines based on the Intel 80x86 family of
processors, the Model 2000 doesn't have a socket for it's co-processor. The
8087 was mounted on a daughtercard, which was then mounted to the mainboard.
It was not possible for the user to do this upgrade, though Envision Designs
did come up with an alternative to the official Tandy upgrade later. Neither
of these upgrades is still available.
25) What are the specifications for the Intel 80186 cpu?
The following was taken directly from Intel order# 210451-003, dated
July 1983 and copyright 1983 by Intel Corporation:
+ Integrated Feature Set
- Enhanced 8086-2 CPU
- Clock Generator
- 2 Independent, High-Speed DMA Channels
- Programmable Interrupt Controller
- 3 Programmable 16-bit Timers
- Programmable Memory and Peripheral Chip-select Logic
- Programmable Wait State Generator
- Local Bus Controller
+ Available in 8 MHz (80186) and cost effective 6 MHz (80186-6) versions.
+ High-Performance Processor
- 2 Times the Performance of the Standard iAPX 86
- 4 Mbyte/Sec Bus Bandwidth Interface
+ Direct Addressing Capability to 1 MByte Memory
+ Completely Object Code Compatible with All Existing iAPX 86, 88 Software
- 10 New Instruction Types
+ Optional Numeric Processor Extension
- iAPX 186/20 High-Performance 80-bit Numeric Data Processor
+ The 80186 is housed in a 68-pin, leadless JEDEC type A hermetic chip
carrier and required the IDT 3M Textool 68-pin JEDEC socket.
Obviously, this is just the very tip of the data, as there are many
pages of diagrams and charts in the document that I've not reproduced here.
26) What are the pinouts for the Model 2000's various ports?
The following was taken directly from Tandy FaxBack document# 1944:
GND = Ground NC = Not Connected * = Active Low Signal
Printer - 34 pin header: Floppy - 34 pin card socket:
1 Strobe* 2 GND 1 GND 2 NC
3 Data 0 4 GND 3 GND 4 In Use*
5 Data 1 6 GND 5 GND 6 NC
7 Data 2 8 GND 7 GND 8 Index*
9 Data 3 10 GND 9 GND 10 Drive Select 0*
11 Data 4 12 GND 11 GND 12 Drive Select 1*
13 Data 5 14 GND 13 GND 14 NC
15 Data 6 16 GND 15 GND 16 Motor On*
17 Data 7 18 GND 17 GND 18 Direction*
19 Acknowledge* 20 GND 19 GND 20 Step*
21 Busy 22 GND 21 GND 22 Write Data*
23 Paper Out 24 GND 23 GND 24 Write Enable*
25 Select* (busy*) 26 Strobe In 25 GND 26 Track 0*
27 GND 28 Fault* 27 GND 28 Write Protect*
29 In 0 30 In 1* 29 GND 30 Read Data*
31 GND 32 In 2 31 GND 32 Side Select*
33 GND 34 Buffer Full 33 GND 34 Drive Ready*
Keyboard - 5 pin DIN: Monochrome - 8 pin DIN: Serial Port - DB-25 Female:
1 Keyboard Data 1 NC 1 GND
2 Keyboard Busy* 2 GND 2 Transmit Data
3 GND 3 Intensity 3 Receive Data
4 Keyboard Clock* 4 Horizontal Sync 4 Request to Send
5 +5V 5 Vertical Sync 5 Clear to Send
6 NC 6 Data Set Ready
Power Connector (2): 7 Video Signal 7 Signal Ground
8 NC 8 Carrier Detect
1 +12V (orange) 9 NC
2 GND (black) Speaker - 2 pin header: 10 NC
3 GND (black) 11 NC
4 +5V (red) 1 Sound 2 GND 12 NC
13 NC
Color Monitor on Mouse Interface on 14 NC
Graphics Board: Digi-Mouse Board: 15 Transmit Clock
16 NC
1 GND 1 GND 17 Receive Clock
2 GND 2 +5V 18 NC
3 Red 3 Switch 3* 19 NC
4 Green 4 X-Axis Phase A 20 Data Terminal Ready
5 Blue 5 X-Axis Phase B 21 NC
6 Intensity 6 Switch 2* 22 Ring Indicator
7 NC 7 Switch 1* 23 NC
8 Horizontal Sync 8 Y-Axis Phase A 24 NC
9 Vertical Sync 9 Y-Axis Phase B 25 NC
27) What operating systems could the Model 2000 run?
Tandy relseased only one version of MS-DOS for the machine, and that was
a special version of MS-DOS 2.11, which went through 3 revisions during the
machines lifetime, the last one being 2.11.03. Tandy sent a service bulletin
out to all registered owners on May 21, 1987 announcing the 2.11.03 upgrade,
stating that is was a 'required' upgrade and that there was a nominal charge
of $9.95 (U.S.) for this upgrade. A PNG image of this bulletin is available
at the homepage for this FAQ.
It is impossible to use a later non-Model 2000 version of MS-DOS, again
due to hardware differinces. One interesting side note about this special
MS-DOS was that it's whole character set was loaded into RAM and there were
shareware/public domain utilities available that allowed you to redefine the
whole character set and load the new fonts at bootup. This made for some
interesting effects, as there were some unusual fonts for it out there! At
various times, there have been reports of people attempting to port or modify
other versions of MS-DOS to function on the Model 2000, though I'm not aware
of any that were successful.
Tandy did sell SCO Xenix for the Model 2000 but it was never advertised
much. It reportedly didn't function well and caused previously unknown bugs
in the Model 2000 to surface, hence a lot of the tech bulletins designed to
fix them.
28) What software was made for the Model 2000?
The following software was either released or in developement for the
Model 2000 as of 11/30/83 (Note: All prices are original list price and
Tandy catalog numbers are shown when known):
a) MS-Pascal compiler - #26-5256 ($299.95)
b) MS-Basic compiler - #26-5251 ($299.95)
c) MS-Fortran - #26-5255 ($349.95)
d) MS-Assembler - #26-5252 ($99.95)
e) MS-DOS Cobol - #26-5257 ($595.00)
f) Multimate - #26-5330 ($249.95)
e) PFS-Write - #26-5309 ($140.00)
f) Microsoft Word - #26-5314 ($375.00)
g) PFS-File - #26-5305 ($140.00)
h) PFS-Report - #26-5306 ($125.00)
i) PFS-Graph - #26-5307 ($140.00)
j) dBase II - #26-5352 ($595.00)
k) Microsoft Multiplan - #26-5311 ($249.00)
l) Videotex Plus - #26-5260 ($49.95)
m) The Home Accountant Plus - #26-5340 ($124.95)
n) Planetfall - #26-5377 ($49.95)
o) The Witness - #26-5376 ($49.95)
p) MAI/Basic Four General Ledger - #26-5210 ($495.00)
q) MAI/Basic Four Accounts Payable - #26-5212 ($495.00)
r) MAI/Basic Four Accounts Receivable - #26-5213
s) MAI/Basic Four Inventory Control - #26-5214 ($495.00)
t) MAI/Basic Four Order Entry - #26-5215 ($495.00)
u) MAI/Basic Four Purchase Order Control - #26-5217 ($395.00)
v) MAI/Basic Four Payroll - #26-5218 ($495.00)
The following appeared later, though this is not a complete list:
a) Lotus 1-2-3 - #26-5300
b) Ashton-Tate Framework - #26-5320
c) dBase III - #26-5353
d) Microsoft Flight Simulator 1
e) Microsoft Windows 1 (requires driver disk, Tandy #7002611)
f) VersaCAD
g) Lotus Symphony
h) Pagemaker 1 (from within Windows 1)
i) Varsity Scripsit for Model 1000/2000 - #25-1174 (released 1987)
j) DR DRAW - #26-5279
k) Graphwriter - #26-5276
29) Can you run IBM-compatible software on the Model 2000?
Most of the time no, but there were a few well-behaved and well written
programs that would run on the Model 2000. The list is far too long to print
here, but at last count in the August 1, 1989 issue of the Whimper, there
were 547 programs of all types that would run on the Model 2000. Obviously,
as of the time this FAQ was written, most of the newer software will not run
on the Model 2000 since the hardware requirements are far above what is
possible on the machine. In general, programs that are meant to run on the
IBM PC-XT, that do not access the video hardware directly, have a good
chance of running on the Model 2000. A good example of a regular IBM
compatible program that could be made to run on the Model 2000 was Wordstar
which required that video be set to use BIOS calls in the setup, as well as
the printer port changed from LPT1: to PRN:. After this, it ran normally.
30) Is it possible to get 'online' with a Model 2000?
Yes, though only for calling a BBS or accessing the Internet through a
UNIX shell account. There is no software for making a TCP/IP connection
directly. A good terminal program, which also doubles as a BBS host, is
called GT-Power. It's quite a powerful package and utilizes a FOSSIL driver
to access the Model 2000's serial port, so the standard IBM version could be
used as long as you're able to find the correct FOSSIL for the Model 2000.
There was an excellent BBS run out of Andrews AFB in Washington D.C. around
1987, called TandyDC, and it was run on a Model 2000 and GT-Power. It must
be noted that there were two varieties of GT-Power produced, one which wrote
directly to the serial port of an IBM-compatible and doesn't require the
FOSSIL driver, and the version that used the FOSSIL driver to access the
serial ports. The Model 2000 can only use the FOSSIL version.
The main choice for running a BBS host on a Model 2000 is GT-Power. Due
to thier usage of a FOSSIL driver though it may be possible to get either
FIDO or OPUS to run on the Model 2000 as well. It should be noted though
that at this stage the versions being referred to are upwards of 10 years
old and may no longer be supported or no longer available online.
31) How can I run Infocom text adventures on the Model 2000?
It should also be pointed out that since Infocom released 'Planetfall'
and 'The Witness' for the Model 2000 that it should be possible to play the
other Infocom games such as 'Zork' and 'Enchanter' on the Model 2000 as
well. This is because the data files between the various platforms remained
the same, the interpreter being platform and not game-specific. An exception
to this are the data files for Macintosh versions. Non-IBM systems such as
the Amiga have used this fact to create a single interpreter capable of
running all of the Infocom text games using the IBM data files. All of the
Infocom text adventure games were at one time available on two CD-ROMs using
the PC data files. The Model 2000's interpreter may not be able to play
later games, as the data format was changed somewhat as additional features
were added. If anyone is able to test this, please let me know what works.
Infocom, which first brought Zork to microcomputers in 1980,
released these games for a wide variety of platforms, including the Atari
8-bit line, Commdore-64, IBM PC-XT, and various CP/M versions including for
the Osborne.
32) Can I run Microsoft Windows on the Model 2000?
The only version of Windows that will run on the Model 2000 is Windows
version 1. It requires a special driver disk, sold by Tandy under part#
7002611. It supported the Model 2000's high resolution graphics as well as
the Digi-mouse. Programs written to run under Windows 1 were then usable on
the Model 2000, such as Pagemaker 1.
33) What are the 'MAI/Basic Four' programs?
The MAI/Basic Four series of programs was a collection of business
programs that were ported to the Model 2000 from thier origins on mainframe
computers. They included modules for general ledger, accounts payable,
accounts receivable, inventory control, order entry, purchase order control,
and payroll. For the small business, they brought a great deal of power to
the Model 2000. See section #28 of this FAQ for the Tandy catalog numbers
for each module. These programs were produced by MAI Inc. in 1983.
There are currently two gaps in the Tandy part numbers that fall
within the range of those for these modules, which I don't know the name of.
Those part numbers are 26-5211 and 26-5216. These missing numbers may or may
not be additional modules for this series. The flyer I have that lists the
various modules doesn't list either of these two or 'Accounts Receivable',
#26-5213, so they may have been released later.
34) Are there any books available on the Model 2000?
At one time there was a book entitled 'Mastering the Tandy 2000'. It
was 154 pages, and carried ISBN number 0-8306-1829-5. It was written by Dan
Keen and Dave Dischert and published by TAB Books in 1984. There are a lot
of programming examples, as well as in-depth data on the 80186 processor by
providing a reprint of the July 1983 Intel datasheet.
Also, there was abook by David A. Lien, 'Learning Basic for the Tandy
1000/2000', which was sold through Radio Shack stores. Both of these books
are long out of print, though with some searching it may be possible to find
a second-hand copy. According to the 'Tandy 1000-series FAQ' by Jeff Hayes
<>, the Basic book by David A. Lien was included as part of a
set of MS-DOS books which carried Tandy part# 25-1508.
Of course, there were also the MS-DOS and Basic handbooks Tandy shipped
with the Model 2000, as well as the 'TRS-80 Model 2000 Service Manual'. This
was a large book, roughly 8-1/2" x 11" and approximately 400 or so pages and
covered all aspects of the Model 2000's hardware, including data sheets from
Intel for the CPU and supporting chips, as well as reference sections for the
Tandon 10meg hard disk and Mitsubishi floppy drives.
35) What 'Tech Bulletins' were sent out by Tandy?
Almost as soon as the Model 2000 started shipping, various bugs in
the system began to appear. As fixes for these problems were developed,
Tandy sent out 'Tech Bulletins' to it's various Service Centers. Supposedly,
if the user brought the machine into the nearest service center for a
problem covered by one of the tech bulletins, it was to be fixed for free.
Oddly, there didn't appear to be a pattern as to which machines needed which
of the modifications performed, so some of them may have been attributable
to the parts quality used at the time of the particular machines production.
My original machine only needed the potentiometer in the PSU replaced to
stop random rebooting. * following the date indicates last revision date.
# Problem Description: Date Released:
--- -------------------- --------------
001 When powered up video is not syncronized 04/18/88 *
002 Improper power lead dress may cause A/C noise 12/08/83
003 Installation of the expansion RAM bank 12/16/83
004 Modification to cure video jitter 12/19/83
005 Memory parity errors caused by U59 02/27/84 *
006 Complete or partial blank video display 01/18/84
007 Modiciation to Rev. PP2 Hires Graphics board 01/16/86
008 Installation of the color chipset 01/18/84
009 Identify proper PAL for Hires operation 07/12/88 *
010 Both floppy drive activity LED's light 01/24/84
011 Shorting power supply pulling system down 03/16/84
012 Component changes on hard drive controller board 04/12/84
013 Assure proper operation of Memory Parity Interrupt 05/10/84
014 To correct timing on external 256k memory board 01/30/85 *
015 To correct blowing of power line fuse 04/11/88 *
016 Ensure proper seating of all PCB's 04/24/85 *
017 Random problems with internal hard drive 09/11/84 *
018 Possible switch wire damage 06/13/84
019 Possible misalignment of CPU chip in socket 07/11/84
020 Parity modification for units with date code AA 10/10/85 *
021 Random dots appearing on color monitor screen 04/24/85 *
022 Installation of hard drive upgrade kit 08/14/84
023 To increase stability of power supply under load 08/21/84
024 Intermittent 'Bad Command Reading Drive C' error 10/10/84 *
025 Eliminate random memory errors on graphics baord 10/16/84
026 Memory timing and refresh problems on ext. RAM PCB 06/28/85 *
027 Test points for new Mitsubishi floppy drive 11/21/84
028 Installation of secondary hard drive 01/29/85
029 'Reflection' of video column zero on right side 04/24/85
030 Insure proper connection of mother board to main PCB 05/22/85
031 To remove possible interrupt conflicts on the bus 02/03/86 *
032 Correct polarity of External Memory Parity Interrupt 11/15/85
033 To prevent a false memory cycle 11/15/85
034 To correct parity latch timing 02/10/86 *
035 Allow installation of two or more serial exp. boards 11/26/85
036 Eliminate timing problem with BUSARDY* signal 12/05/85
037 Eliminate data errors on the serial exp. board 12/06/85
038 8087 numeric coprocessor upgrade procedure 01/06/86
039 Identifying faulty 80186 CPU chips 03/12/86 *
040 False trigger could cause garbage to be written to HD 12/30/85
041 Improve stability of VCO 01/22/86
042 Eliminate random reboot because of power supply 03/26/86 *
043 Substitution of 2000 keyboard with Tandy 1000 keyboard 04/15/86
044 Allow hard disk controller to use external drive C: 09/08/87 *
045 Enable proper modem operation 11/19/87
046 Permit use of Samsung RAM chips & reduce parity errors 06/01/88 *
The Tandy 2000 Orphans originally distributed the above bulletins bound
into a single package, which is where the above list was taken from. A PDF
of this package is available at the homepage for this FAQ,
36) Where can I get support for this machine?
The best place to get support is Usenet in comp.sys.tandy. A number of
people who frequent that newsgroup have a great deal of knowledge concerning
this machine. If you're in need of a replacement MS-DOS 2.11.03 disk, as of
September 1999 they could still be ordered from Tandy by calling
1-800-433-2024 for Tandy Software Exchange and giving them part# 700-2701.
A company called 'Pacific Computer Exchange' in Oregon used to deal
quite a bit in Model 2000 parts. They're old contact information is:
Pacific Computer Exchange
1031 S.E. Mill St., Suite # B
Portland, OR 97214
Phone: (503) 236-2949
Also, from 1987 until 1990, there was a user's group called the 'Tandy
2000 Orphans' who published a monthly newsletter called the 'Whimper'. The
group exchanged hardware and software hints and tips. It was disbanded and
the newsletter ceased publication after 22 issues. The newsletters are a
great souce of information though. At the time the group disbanded, the last
issue of the 'Whimper' reported that there were nearly 350 active members
and another 220 inactive members. The group billed itself as the 'worlds
largest single machine user-group'. A sample newsletter in PDF format is
available at the homepage for this FAQ,
At one point, some in the Tandy community looked on the Orphans as
being software pirates, but this was not true. Though software for the
Model 2000 was advertised through the 'Whimper' and provided by the group to
it's member's, only members who provided proof of already owning the product
could order certain items that were considered commercial. At the time,
companies such as Ashton-Tate and Lotus Development Corp. relied heavily on
on-disk copy protection, so one of the things the group provided to
legitimate owners was un-protected program disks which could be backed up.
Since the Model 2000 versions of these programs were no longer available by
this time, data loss due to not being able to use an original program disk
was quite a problem. Framework, Lotus 1-2-3 and Microsoft Flight Simulator
were just a few of the programs which were Model 2000-specific versions
which used on-disk copy protection and could not normally be copied or
backed-up. One of the popular on-disk protection schemes at the time
involved a counter which kept track of how many times the program had been
installed. If the counter showed more more than one or two installations,
the install program would abort. The only way to reset the counter was to
use the same disk to uninstall the software. Ashton-Tate used this type of
protection with it's integrated package 'Framework'. It's easy to see how
one could easily lose the ability to use the program through legitimate
problems such as disk errors that required re-installation.
Envision Designs stopped manufacturing thier memory products and 8087
coprocessor board in 1990.
37) What is 'Envision Designs'?
Envision Designs was run by Dave Nechodom in the late 1980's and
produced hardware upgrades for the Model 2000. These upgrades included
various RAM upgrades as well as a math coprocessor upgrade. In 1990, the
company decided that the market for these products had grown too small to
warrant further support, so further sale of all products for the Model 2000
was dropped. At the time, it was rumored that the procedures for doing the
various modifications to the machine would be made available to the Orphans
usergroup. Unfortunately, this never happened and these upgrades and
modifications are no longer available to Model 2000 owners. Supposedly there
was at least one text file circulating that described how to modify the
standard #26-5161 memory expansion board to hold a full 640k, but
unfortunately I have been unable to locate a copy of it.
38) What is 'Microlink Technology'?
Microlink Technology was run by Bob Spencer and, among other things,
produced software for the Model 2000 and sold it in the Whimper newsletter.
His main item for the Model 2000 was a program called MLFormat, which
allowed the Model 2000 to format and use hard disks larger than 32MB. He
also sold replacement ROM chips for the 2000's mainboard which fixed a
number of bugs, including allowing it to display the correct amount of RAM
at boot if one of the Envision 896k RAM upgrades was installed. Another
piece of software he sold for the 2000 was 'Mousetrap' which allowed the
Digi-mouse to be used in place of the arrow keys, ENTER key or F1 function
key and in nearly any program, even if it didn't support the mouse.
39) Future plans for this FAQ include:
a) Details on any hardware modifications, other than 'tech bulletins'
b) The addition of any other software and/or hardware specifically for
the Model 2000 that I learn the existence of.
c) Details concerning the developement of the Model 2000. Can anyone
supply information concerning this area??
That's it for this version of the FAQ. I will update this as I find new
information. Comments, suggestions, and corrections are welcome! I would
also be indebted to anyone that could provide me with Microsoft Flight
Simulator-1 for the Model 2000.
Copyright (2005) by Jeff Hellige (
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