website/content/museum/digital-equipment-corporation-300-professional-series.md

---
title: Digital Equipment Corporation 300 Professional series
categories:
- Computers
types:
- Professional Computer
origins:
- U.S.A.
years:
- '1982'
cpus:
- DCF-11 chipset
params:
  name: 300 Professional series
  image: /media/museum/photos/digital_pro300_proc_system_1.jpg
  company: /companies/digital-equipment-corporation
  company_name: Digital Equipment Corporation
  specs:
  - label: NAME
    value: 300 Professional series
  - label: MANUFACTURER
    value: Digital Equipment Corporation
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: June 1982
  - label: END OF PRODUCTION
    value: Unknown
  - label: BUILT IN LANGUAGE
    value: None
  - label: KEYBOARD
    value: Full-stroke 106 keys keyboard with 20 function keys, editing and numeric keypads
  - label: CPU
    value: DCF-11 chipset (325/350) - Harris J-11 chipset (380)
  - label: SPEED
    value: 13.33 MHz. (325 - 350), 15 MHz. (380)
  - label: CO-PROCESSOR
    value: MMU and FPA (belong to the DCF-11 chipset)
  - label: RAM
    value: 256 KB (up to 1 MB)
  - label: VRAM
    value: 32 KB
  - label: ROM
    value: 12 KB (contains power-up self test code, configuration & initialisation code and boot code)
  - label: TEXT MODES
    value: 80 x 24 / 132 x 24
  - label: GRAPHIC MODES
    value: 1024 x 256 dots.
  - label: COLORS
    value: '256'
  - label: SOUND
    value: Although there wasn't a sound port, there was an option known as the Telephone Management System (TMS). It could be programmed to be used as a modem, but it also could be programmed to play and record sounds - one application turned it into essentially an answering machine - playing an outgoing message from a disk file, and recording incoming voice data to a file.
  - label: SIZE / WEIGHT
    value: 58(W) x 36(D) x 17(H) cm. (Mainframe)
  - label: I/O PORTS
    value: Video output, Keyboard, Printer output (which could also be used for a debugging terminal), RS232, 6 expansion slots
  - label: BUILT IN MEDIA
    value: |-
      325: 2 x 5.25 400 KB FDD\
      350: 2 x 5.25 400 KB FDD - 1 x 10 MB HDD\
      380: 2 x 5.25 400 KB FDD - 1 x 20 MB HDD
  - label: OS
    value: P/OS, RT-11,, Venix
  - label: POWER SUPPLY
    value: Built-in PSU
  - label: PERIPHERALS
    value: Unknown
  - label: PRICE
    value: |-
      Pro 325 : about US$8,000\
      Pro 350 : about US$10,000
  tabs:
  - photos
  - adverts
  photos:
  - title: MODEL 350
    subtitle: ''
    text: Running boot-up hardware self test.
    image: /media/museum/photos/digital_pro350_selftest_1.jpg
  - title: CLOSE-UP
    subtitle: ''
    text: Note the function-key labels of WPS-PLUS/POS, a word processing system from Digital.
    image: /media/museum/photos/digital_pro350_keyb_closeup_1.jpg
  - title: REAR CONNECTORS
    subtitle: ''
    text: |-
      **(1)** Keyboard connector\
      **(2)** Mainframe link connector\
      **(3)** Bright and contrast adjustments\
      **(4)** Local network DB15 connector\
      **(5)** TMS connectors (see TMS module)\
      **(6)** Serial RS232C DB25 connector\
      **(7)** Parallel printer DB9 connector\
      **(8)** Monitor DB15 connector\
      **(9)** Hardware test leds\
      **(10)** Mains plug and voltage selector
    image: /media/museum/photos/digital_pro350_rearconnect_1.jpg
  - title: INSIDE
    subtitle: ''
    text: |-
      The inside of the DEC is very modular and well organized. Each component can be removed without any tool help.\
      From left to right, you can see the power supply unit, hard disk drive (Seagate 10 MB - ST412), and dual floppy drive unit.
    image: /media/museum/photos/digital_pro350_inside_1.jpg
  - title: EXPANSION BOARDS
    subtitle: ''
    text: |-
      Six card can be inserted in the expansion cage. Three of them (**1**, **2** and **3**) are original parts of the 350 system.

      **(1)** Hard disk controller card\
      **(2)** Floppy disc controller card\
      **(3)** Video card\
      **(4)** 512 KB expansion memory board\
      **(5)** TMS management and software card (see TMS module)
    image: /media/museum/photos/digital_pro350_extcards_1.jpg
  - title: TMS MODULE
    subtitle: ''
    text: |-
      The **T**elephone **M**anagement **S**ystem is an optional integral modem/voice unit that fits into a special slot of the system. It adds a voice communication port and an additional data communication port to the system.

      The Telephone Line Interface (TLI) module supplies four connectors. Two jacks are the telephone lines 1 and 2 (**1**), one for the phone handset (**2**) and one DIN plug for the TMS speaker (**3**).\
      TMS module supported live voice communication or encoded voice/music support for recording and playback.\
      A switch (**4**) allowed TMS to be enabled/disabled.

      Note also the clock battery backup (**5**)
    image: /media/museum/photos/digital_pro350_modemext_1.jpg
  - title: MAIN BOARD
    subtitle: ''
    text: |-
      Main board can be easily removed from the case.\
      It is here fitted with 2 x 512 KB RAM daughter boards.
    image: /media/museum/photos/digital_pro350_motherboard_1.jpg
  - title: EXPANSION CONNECTORS
    subtitle: ''
    text: ''
    image: /media/museum/photos/digital_pro350_expslots_1.jpg
  - title: DCF-11 CHIPSET
    subtitle: ''
    text: |-
      DCF-11 chipset consists of the DCF-11 16-bit main processor, a memory management (MMU) and floating point (FPA) coprocessors.

      This chipset was used in 325/350 models, but also in DEC PDP-11/23 and 11/24 systems.
    image: /media/museum/photos/digital_pro300_proc_closeup_1.jpg
  - title: USER MANUALS
    subtitle: ''
    text: A complete set of manuals provides all necessary hardware and software information to the beginner as well as the advanced user.
    image: /media/museum/photos/digital_pro350_manuals_1.jpg
  adverts:
  - title: US ADVERT, JULY 1985
    subtitle: ''
    text: |-
      DEC Advertises its range of networking products.

      Byte magazine
    image: /media/museum/pubs/digital_pro350_pub_s1.jpg
  oc_id: 115
  source:
    url: https://web.archive.org/web/20230608092713/http://www.old-computers.com/museum/computer.asp?c=115
    date: '2023-06-08'
---

In conceiving the Professional 300 series, DEC designers decided that new machines must be able to perform several tasks at once, apply the same user interface, communicate efficiently and use the same software as Digital's popular microcomputers.

These personal computers were really desktop-sized versions of the PDP-11, one of Digital's popular minicomputer. Both models shared the PDP-11 instruction set and memory management. Both had an operating system based on Digital's RSX-11M+. For the user, this meant that software applications developped for more than 500,000 PDP-11 and VAX systems were candidat for easy migration to a desktop personal computer.

The members of DEC 300 Pro series were the **325** (two 5.25" disk drives, 400 KB each, and 1 expansion slot), the **350** (one 5.25" disk drive, 10 MB hard disk and 5 expansion slots) and the **380**. The 325 and 350 used the F-11 CPU running at 13.33 MHz (the external clock actually ran at 26.66 MHz). The 380 used the J-11 CPU

About the number of colours: the three planes gave 8 colors at one time by referencing an 8 entry palette.Each entry in the palette could be programmed for one of 256 colors (by setting RGB values).

The internal card cage had space for up to 6 options total, and the base 350 system with EBO used four. The base 380 system used two. A Z80 card was available and allowed to use CP/M as the OS.

The operating systems which ran on it were P/OS (which was a variation of RSX), RT-11 and a variation of Unix called Venix. P/OS and Venix are freely available nowadays. RT-11 is still licensed software and is still being developed and maintained.

These systems were originally sold as standalone units, but were later incorporated into the VAX 8000 series as the system “Console”

Thanks to Megan Gentry, Former RT-11 Developer, who helped us 'debug' this page ;-)