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I am no longer active in this hobby for the foreseeable future. 
I will no longer maintain or update the website, but I will leave it accessible to the web for as long as possible (years).


DG Systems
System Cards
Printer A & B
Disk Drives
Magazine Ads

Mark-8 Minicomputer
MOS Kim-1
Imsai 8080
TV Typewriter
The Digital Group



Digital Group Documentation 

I have piles of DG catalogs and documentation that I have begun to scan for preservation and fun, this page represents my progress in that effort. All scans were done by me unless otherwise noted.

If you find any of the information unreadable or missing pages, please let me know. Some of the documentation has known issues, but as I am aware of them, I will try to fix them or note them here.

Also available are machine readable audio files for loading software into the DG operating system. See my DG Software page.

Most scans were done at 200-600 dpi, depending mainly on when they were scanned. Some of the pdfs are searchable, but most are not. And, as always MORE TO COME! :)

Please Be Kind...

I have limited bandwidth! Download only what you know you want or need, and take your time--only download what you need right now, then save what you download so you need not download it again. Thanks, and enjoy!

2009-01-11_dg_docs 005.jpg (3018481 bytes)
Documentation in pretty Digital Group Binders

To download these files: 

Right click on the file, and choose the option to "Save Target As...", then choose an appropriate directory on your computer. 

The Suding Papers...

suding_scans.pdf - 1.9 Meg The earliest of all dg documents!! These are scans of Dr. Sudings hand-drawn plans for dg equipment, and a couple Mark-8 items.
suding_letters.pdf - 648 KB
Letters written to/from Dr. Suding. One from Jon Titus - Creator of the Mark-8 Minicomputer! (The letter dated January 11, 1974 obviously should read 1975.)

Digital Group Flyers

Flyers have their own page

Digital Group Magazine Ads

Magazine Ads have their own page

Hand drawn motherboard layout plans--Suding Scans


JUDGE - Coming soon.

Bridge - Coming soon, & etc.

DG2 - Coming soon, eventually.

digital group clearinghouse - Coming soon, still.

Digital Group Software Documentation

Software docs has it's own page.

Digital Group Hardware Documentation

Pre-DG "System" Hardware

dg_packet.pdf - 2.4 Meg The original "Packet #1" for making improvements to the Mark-8 Minicomputer. This was the beginning of the digital group. Scans from my original copy, given to me by the author, Dr. Robert Suding.


Bytemaster_Knob.PDF - 886 KB Made doc this for a friend, so he could make a new knob.

DG Systems

dg_systems.PDF - 1.4 Meg This is the systems documentation, covering the board interconnections and front panel.
tech_flyer-updates.pdf - 2.1 Meg Updates and system notes. Stuff they forgot to tell you. Read this first, sort of thing.
dg_chassis.PDF - 23 Meg Cabinet assembly and wiring.
keyboard.PDF - 1.9 Meg Cabinet assembly, schematics.
rs_keyboard.pdf - 3.5 Meg Radio Shack keyboard, my original. Remember when Radio Shack sold stuff like this?
monitor.PDF - 2.3 Meg Video Monitor cabinet assembly, and connection to the system.
basic_box.pdf - 164 KB A simple DG cabinet on a budget.
unrom.pdf - 211 KB Disable the DG ROM, has particular use in Z80 /8080 systems to free up page zero for programming.

Power Supplies

dg_12a_power.PDF - 285 KB 12 Amp +5 Volt supply.
dg_6a_5v_power.pdf - 133 KB 6 Amp +5 Volt Supply
low_current_pwr.pdf - 1.4 Meg Low current supply for all other required voltages.

 dg_ebay_l017.jpg (172486 bytes)
Restored Digital Group System with cover off

System Cards

6500 Series CPU

6502_CPU_Construction.PDF - 19.5 Meg (Same as 6800)
6502-01_OpSys.PDF - 3.1 Meg Operating system, with listings and ROM code.
6500-10A_MCS6500hwMan_Jan76.pdf - 8.2 Meg MOS Microcomputers Hardware Manual.
6500-50A_MCS6500pgmManJan76.pdf - 10.7 Meg MOS Microcomputers Programming Manual.

6800 CPU

6800_CPU_Construction.PDF - 19.5 Meg (Same as 6502)
6800_OpSys.PDF- 8.0 Meg Operating system, with listings and ROM code.
6800_Instruction_Set.PDF- 85 KB Made this myself. No warranty! :)

A Typical DG system

A typical DG Z80 system document package for an audio based system consisted of the following:


parallel _io_card.pdf

8080 CPU

8080_cpu.PDF - 288 KB No further details, just what you see folks.
8080_op_sys.PDF- 4.2 Meg Operating system, with listings and ROM code.


z80_cpu.PDF - 2.9 Meg
z80opsys_32char.PDF - 2.4 Meg Operating system, with listings and ROM code.
z80opsys_64char_new_ver.pdf - 2.6 Meg Operating system, with listings and ROM code, new version.
z80_distribution_cassette.pdf - 431 KB Information on the programs included on the OpSys cassette.

I/O Cards

parallel _io_card.pdf - 2.1 Meg Four port I/O card.
Serial I/O card pdf coming soon.

Memory Cards

8k_mem.PDF - 607 KB
32k_static.PDF - 5.4 Meg
32k_dynamic.pdf - 2.9 Meg

Video Cards

tvc_64.pdf - 6.0 Meg Most common of the available video cards offered by dg.
tvc-32.pdf - 1.8 Meg The earlier TVC card, and the less expensive -- My original.
M6570_video_rom.pdf - 2.5 Meg Video ROM used in most dg video cards.
tvc-32_to_64char.pdf - 69 KB How I modified my TVC-32 to display 64 X16 characters. These are my original notes (nice handwriting!), this was before I designed the clock-doubler to avoid having to buy a new crystal.

Other Cool Cards

votrax_card.PDF - 6.0 Meg Very cool.

Storage Systems


diskmon.PDF - 3.6 Meg Version 1.0 documentation, anyone have anything later?
dd_floppy_controller.PDF - 14.7 Meg Very rare item, Double Density Disk Controller, released just before the company demise.
double_dens_install_man.pdf - 1.4 Meg
hmon.pdf - 2.3 Meg
Hardware Monitor. Diagnostic program used to develop the DG Double Density Disk Controller.
floppy_disk_cabinet.PDF - 6.2 Meg
floppy_disk_cabling-shugart.PDF - 849 KB
floppy_disk_controller.PDF - 11.8 Meg This is the most common disk controller.
floppy_disk_power.PDF - 1.3 Meg
mini_floppy_cabinet.pdf - 3.6 Meg
mini_floppy_drive.PDF - 2.3 Meg Very uncommon. DG used MPI (Micro Peripherals, Inc.) drives.
mini_floppy_power.PDF - 517 KB
nec_controller_chip.PDF - 2.4 Meg Used in the standard floppy controller.
wd_dd_controller_chip.PDF - 2.3 Meg Used in the Double Density Disk Controller.
Shugart_SA400_OEM_Sep78.pdf - 2.9 Meg From bitsavers.org. I don't know if this drive was ever used in a dg system.
Shugart_SA400_Service_Apr79.pdf - 4.0 Meg Ditto & etc.
Shugart_SA800_Maint_Feb78.pdf - 3.8 Meg More bitsavers. I have several copies of this, but this one has already been scanned!
Shugart_SA800_OEM_May80.pdf - 2.0 Meg Ditto.
Shugart_SA800_Parts_May77.pdf - 460 KB Ditto.
Shugart_SA800_TheorOp_May78.pdf - 1.2 Meg Ditto.


phi-deck_card.pdf - 10.7 Meg Ahh! The Phi-deck! I still don't have mine working. I spend too much time scanning documents. :)
phideck_cabinet.pdf - 294 KB Cabinet assembly.
hughies_hot_tips2.pdf - 7.0 Meg A staggeringly complete essay on the Phideck system, and how to make it work to spec., by Hugh Macdonald.
phimon_start.pdf - 0.6 Meg "Getting Started With <Phimon>" Or, how to start Phimon for the first time.
phimon.pdf - 10.5 Meg Phimon operating system documentation.
phimon_upgrade_program.pdf - 91 KB Upgrade instructions to Ver 2.

Digital Group Printer

printer_unpacking.pdf - 0.2 Meg Initial inspection and a few documentation corrections -- Don't skip.
printer_addendum.pdf - 0.2 Meg Important information, and some PC board changes -- Don't skip.
printer_revisions.pdf - 1.1 Meg Changes to the board, corrections, software, etc., &etc.
printer_revisions_addendum.pdf - 0.3 Meg Corrections to the corrections... :)
printer_dg.pdf - 1.6 Meg At last! The actual printer documentation... Careful! Read all the corrections and changes!
- 0.8 Meg Printer driver, "Short Version" -- The name of the document, not my comment. :)
printer_cabinet.pdf - 6.8 Meg Putting it all into the DG cabinet.
- 2.6 Meg The users manual from Practical Automation.


order_examples.pdf - 491 KB Several order confirmations on DG stationary, just for fun.


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Copyright 2008 Bryan's Old Computers
Last modified:
October 16, 2009