Latest updates:
02/04/2017 - Troubleshooting section added
09/27/2016 - Updated About Myself

Welcome to the AT&T PC 6300 home page! This site is dedicated to the celebration and preservation of the AT&T PC 6300, a special IBM PC clone.
This site will be especially helpful for people looking for information regarding the AT&T PC 6300, as well as downloads and pictures. Scans of manuals, magazines, and more will come on down the line as well.
What better of a place for the history of the AT&T PC 6300 than right here on the home page? I can only validate what I state in the following paragraphs with scans of pages from this-n-that advertising and such. Any official history on the PC 6300 is hard to come by online, including design information.
The AT&T PC 6300 was introduced by AT&T (American Telephone and Telegraph) in 1984 designed as competition to the IBM PC, introduced in 1981. The PC 6300 was designed primarily for business use, but was a fine canidate for a home computer as well.  
The AT&T PC 6300 was AT&T's 1984 approach to answering and competing against IBM's PC 5150, introduced in 1981. For better or worse, the breakup of Ma Bell had forced giant AT&T to crawl out from under the monopolistic blanket of protection and into the competitive high-technology arena. AT&T had taken its size, household name, budget, and reputation for quality into the computer marketplace with the 6300, an imported Olivetti-made IBM PC compatible.
The AT&T PC 6300 was AT&T's first attempt at making an IBM PC compatible, and it did a fabulous job with it. AT&T built a solid IBM-PC compatible based on what worked in the past, what workes now, and what the future needed. (speaking as if this is 1984)
The 2-piece case opens on top to reveal the 7 slot expansion daughterboard, including 2-3 16-bit ISA slots, built-in video card, 110V PSU, and disk drives. The bottom cover opens revealing an 8MHz 8086 processor, a battery-backed clock and calender, up to 640K worth RAM banks, an opening for the optional 8087 NPU, and so much more, all in a case a little longer front-to-back than the IBM, but quite a bit smaller side-to-side. Note that the 16-bit expansion bus accepts boards proprietary to the IBM PC-AT design.
The AT&T PC 6300 contains another key set of features that combines the IBM PC and IBM PC-AT together. The detachable keyboard contains indicator lights on both CAPS lock and NUM lock, whereas the rest of the keyboard mimics IBM's design.
The other key feature of the AT&T PC 6300 is it's video card. Proprietary though it may be, it can control either a monochrome or color monitor at resolutions up to 640x400.Find a chart below detailing it's capabilities.
640x400 in characters.
640x200 in monochrome graphics
320x200 in color graphics (4-color)
GWBASIC Proprietary graphics
640x400 high-resolution monochrome
640x400 high-resolution color
80x25 alphanumerics display
8x16 character font
Character attributes:
High Intensity
As is to be expected, the AT&T 6300 is a true IBM PC compatible and runs most off-the-shelf IBM PC software. To make a long story short, the computer runs Lotus 1-2-3 version 1A, Microsoft Flight Simulator, Ashton-Tate dBase III and Framework, Borland Turbo Pascal and Sidekick, Hayes Smartcom II, and many, many more programs.
Pricing information on February 20th, 1985(actual purchase price on receipts):
AT&T PC 6300 Model 1:  128K RAM & Dual 360K drives
with High-res color monitor:        $1991.50
256K Byte Board:                    $420.00
128K Byte chip:                     $280.00
Keyboard:                           $105.00
MS-DOS package(w/GW BASIC):         $65.00*
AT&T PC 6300 mouse:                 $110.64
*This represents a one-time right to use fee, NOT purchase price
Prices include N.P.A. discount
From the folder included with any new PC 6300:
"The AT&T Personal Computer:
A multi-purpose productivity tool.
    The new AT&T Personal Computer Model 6300 exemplifies this commitment to raise your organization's productivity. A member of the AT&T family of computers, it plays an integral part in the new AT&T Information Systems' commitment to provide total information movement and management systems. The AT&T PC delivers amazing power and versatility on the desk top. What's more, its operational compatibility with leading personal computers offers a wide range of business solutions while maximizing the use of your existing software and data processing resources."
The AT&T PC 6300 is capable of running MS-DOS, Concurrent PC-DOS, UNIX, and even CP/M 80. With it's versatility, it made an excellent choice for the business enviroment. 8 expansion slots (including 2(3 on later models) 16 bit slots) made it even better, allowing for many expansion options, including a card to allow the AT&T PC 6300 to assosciate with an AT&T 3B2 computer, and to network with many computers in a workplace. For added compatibility, a 16 to 8-bit data bus converter was right on board, making the AT&T PC's 16-bit architecture compatible with industry standard 8088-based option cards. The AT&T PC 6300 cames standard with 128K of RAM, capable of 640K by either adding chips on board, or by adding a memory expansion card($420). The PC 6300 also came standard with a single half-height 360K floppy drive, but is capable of handling 2 360K drives, or a single 360K floppy drive and a 10MB HDU(up to 50MB on later models). Built in color support, integrated parallel and serial ports, and a battery-backed clock/calender made the AT&T PC 6300 even better. An 8086 processor, at 8MHz powered this all on a high-throughput 16-bit data bus.
The AT&T PC 6300 claims 100% compatible with all PC programs and cards, including Microsoft Flight Simulator and Lotus 1-2-3. What's more, it has support for even more cool features. It supports up to 640x400 high resolution color (incredible for 1984! Most computers didn't do this until Windows 95!) and even has a built in mouse port. For a mere $105, one could add this fantastic mouse to their AT&T PC 6300. The disk included a setup program to allow you to custom-configure the mouse to your liking, and save seperate settings. The disk included a very cool drawing/editing program as well. Want to use the mouse but dont have any programs to support it? No matter! The AT&T PC 6300 mouse can emulate the pressing of the arrow keys on programs without mouse support.
The mouse claims support with most programs, but I've found a bug in it. It isn't a nasty cockroach though, more like a ladybug. If you run the mouse setup program before starting Microsoft Flight Simulator, by moving the mouse the game pauses as if you hit "ESC." To solve this issue, simply do not run the mouse setup program before running Microsoft Flight Simulator. If you've already done it, simply reset.
Creative Computing VOL. 11, NO. 6 / June 1985 / PAGE 32
AT&T PC 6300 information folder (included with all 6300 systems)
ATTIS receipts