---
title: ATT Unix PC
categories:
- Computers
types:
- Professional Computer
origins:
- U.S.A.
years:
- '1985'
cpus:
- Motorola MC68010
params:
  name: Unix PC
  image: /media/museum/photos/att_unixpc_system_s1.jpg
  company: /companies/att
  company_name: ATT
  specs:
  - label: NAME
    value: Unix PC
  - label: MANUFACTURER
    value: ATT
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: '1985'
  - label: BUILT IN LANGUAGE
    value: Bourne Shell Scripting, C and ASM with optional Software
  - label: KEYBOARD
    value: Detachable 103-key QWERTY
  - label: CPU
    value: Motorola MC68010 (16 bit external bus, 32bit internal) with custom MMU
  - label: SPEED
    value: 10 MHz
  - label: CO-PROCESSOR
    value: Custom Gate Arrays for DMA (3), 8088 (86?) on optional DOS-73
  - label: RAM
    value: 512 KB / 1 MB / 2 MB / 4 MB
  - label: ROM
    value: 16 KB EPROM holding Boot Strap, Diagnostics etc.
  - label: TEXT MODES
    value: 80 columns x 29 rows
  - label: GRAPHIC MODES
    value: 348 x 720 on built-in 12'' Monitor
  - label: COLORS
    value: Green On Black Monochrome
  - label: SOUND
    value: Beeper
  - label: I/O PORTS
    value: Centronics, RS-232c, Tip/Ring Line Modular Phone Jacks (2), RJ11 Phone Jack (1). Internal Expansion Slot (3), Internal 300/1200 bps modem
  - label: BUILT IN MEDIA
    value: 10 or 20mb hard drive then later 40 and 67mb hard drive. 5 1/4
  - label: OS
    value: AT&T Unix v3.51, Unix based on System V r2 with extensions from BSD 4.1, BSD 4.2, SysV r3 and Convergent Technologies
  - label: POWER SUPPLY
    value: Built-in PSU
  - label: PERIPHERALS
    value: |-
      Three button optomachanical mouse\
      Ethernet\
      DOS-73 board, 512kb RAM board, 2mb RAM board, Dual EIA Port board\
      EIA/RAM Combo board\
      23 MB Tape Drive
  - label: PRICE
    value: |-
      $5590 for 10mb HDD, 512Kb RAM and Unix\
      $6590 for 20mb HDD, 1mb RAM and Unix\
      $1195 for 512kb expansion card
  tabs:
  - links
  forum_thread: 1134
  links:
  - title: AT&T 7300/3b1 (UNIXPC) Stuff
    url: http://www.unixpc.org/
    text: ''
  - title: Unix PC Archive Holdings
    url: http://unixpc.taronga.com/
    text: ''
  oc_id: 1164
  source:
    url: https://web.archive.org/web/20230328011733/http://www.old-computers.com/museum/computer.asp?c=1164
    date: '2023-03-28'
---

The AT&T UnixPC was AT&T's attempt to get into the business computer market of the mid-1980s. There were two flavors of this machine: the **7300**, and the **3B1**. Basically the circuitry is identical in both machines however the 3B1 allowed more room for hard-drive storage, as shown with the ominous bulge underneath the screen. (not shown in model above).

The windowing manager was absolutely wonderful keeping the UNIX system well hidden, however, you could naturally open a shell and interface directly. The graphics system was neat as well - there is a 3D bitmap demo online somewhere.

These computers could support 3 terminals with an add-on card for concurrent use by up to 4 users (one at he console, one on the built-in port, and one each on the two add-on ports).

The keyboard could be "nested" on the shelf in front of the floppy drive. The sound was limited to beeps.

There was also an add-on board with a speech synthesizer which could turn the UnixPC into a full-fleged voicemail management system.

An absolutely wonderful and advanced computer for it's time, which can still teach modern computers a lesson in innovation.

---

**Contributors:** Domenic Schipani, Gary Clouse

<table> <tr> <td></td> <td>We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.</td> <td></td> </tr> </table>