ADM-3
   HOME

TheInfoList



OR:

The ADM-3A was an influential early
video display terminal A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and ...
, introduced in 1976. It was manufactured by
Lear Siegler Lear Siegler Incorporated (LSI) is a diverse American corporation established in 1962. Its products range from car seats and brakes to weapons control systems for military fighter planes. The company's more than $2 billion-a-year annual sales come ...
and had a 12-inch screen displaying 12 or 24 lines of 80 characters. It set a new industry low single unit price of $995. Its "
dumb terminal A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and ...
" nickname came from some of the original trade publication advertisements. It quickly became commercially successful because of the rapid increase of computer communications speeds, and because of new
minicomputer A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
systems released to the market which required inexpensive operator consoles.


History

Lear Siegler, Inc. (LSI) manufactured its first
video display terminal A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and ...
in 1972 – the 7700A. In 1973, LSI hired a new head of engineering, Jim Placak. He and his team created the ADM-1 later that year. It set a new pricing low in the industry at $1,500. Its lower cost was primarily due to a unique single printed circuit board design. In early 1973 the LSI division in Anaheim, California that manufactured these and other products hired a management team for this product line – a VP, national sales manager, and one regional sales manager – for the western region. The ADM-1 was followed by the ADM-2 in early '74. It had expanded functionality and a detached keyboard. The initials "ADM" were referred to as meaning "American Dream Machine" in some advertising.


ADM-3

The ADM-3 followed and the first manufactured units were introduced at 1975 National Computer Conference in Anaheim, Calif., May 19–22, 1975, in booth 2348 at a price of $995. Its innovative wave soldered single board design, which included the keyboard and all connectors, was packaged in an original clam shell enclosure. Within weeks of the launch of the ADM-3, Cagan started to book very large orders. Its 'Dumb Terminal' nickname came from some of the original trade publication ads, and quickly caught on industry wide. Due to two emerging trends the device immediately became the best selling in the industry. Computer communications speeds were rapidly increasing, and a wave of general purpose and dedicated single application
minicomputer A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
systems were hitting the market from dozens of manufacturers. These required inexpensive operator consoles that could match the speeds. With no fast low cost printers available, the ADM-3 (painted in a variety of custom colors for the
OEM An original equipment manufacturer (OEM) is generally perceived as a company that produces non-aftermarket parts and equipment that may be marketed by another manufacturer. It is a common industry term recognized and used by many professional or ...
s) became the de facto standard. By December 20, 1976, the widely used Teletype Model 33 KSR electromechanical printing terminal, which could only print ten characters per second, sold for $895 or $32/month, while the ADM-3, which could display up to 1,920 characters per second, went for $995 or $36/month.


ADM-3 options

The original ADM-3 terminal displayed only capital letters. In 1976, an option was added to allow it to display both lower and upper case. The standard version of the terminal displayed only twelve (rather than twenty-four) rows of eighty characters. In those days RAM was expensive, and halving the display size halved the RAM requirement (and likewise all uppercase required only six bits per character to be stored rather than seven). Further optional add-ons included a
graphics card A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer moni ...
enabling it to emulate a
Tektronix 4010 The Tektronix 4010 series was a family of text-and-graphics computer terminals based on storage-tube technology created by Tektronix. Several members of the family were introduced during the 1970s, the best known being the 11-inch 4010 and 19-inc ...
and an extension port which would allow daisy chaining several ADM-3As on a single
RS-232 In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such a ...
line.


ADM-3A

In 1976, the ADM-3A was introduced. The ADM-3A added support for control codes to move the cursor around on the screen, and directly position the cursor at any point in the display. It did not, however, support “clear to end of line” or “clear to end of screen”, or other more advanced codes that appeared in later terminals, such as the
VT52 The VT50 was a CRT-based computer terminal introduced by Digital Equipment Corporation (DEC) in July 1974. It provided a display with 12 rows and 80 columns of upper-case text, and used an expanded set of control characters and forward-only scro ...
and
VT100 The VT100 is a video terminal, introduced in August 1978 by Digital Equipment Corporation (DEC). It was one of the first terminals to support ANSI escape codes for cursor control and other tasks, and added a number of extended codes for special f ...
. The ADM-3A's overall setup was controlled by 20
DIP switch A DIP switch is a manual electric switch that is packaged with others in a group in a standard dual in-line package (DIP). The term may refer to each individual switch, or to the unit as a whole. This type of switch is designed to be used on a ...
es under the nameplate at the front of the machine, beside the keyboard, including speed from 75 to 19,200 baud. The advanced configuration options allowed split speed connection, sending at one rate, and receiving at another.


Hardware

The 5×7 dot matrix characters were displayed in amber, green, or white
phosphor A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or vi ...
on black (the cursor was 7×9). The keyboard had 59 keys. The 12-inch
monochrome A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, monochrom ...
CRT was mounted in the top half of the case, which was hinged in the back and opened like a clamshell. The CRT was typically made by
Ball Brothers The Ball brothers (Lucius, William, Edmund, Frank, and George) were five American industrialists and philanthropists who established a manufacturing business in New York and Indiana in the 1880s that was renamed the Ball Corporation in 1969. ...
. Unlike later terminals, such as the
VT100 The VT100 is a video terminal, introduced in August 1978 by Digital Equipment Corporation (DEC). It was one of the first terminals to support ANSI escape codes for cursor control and other tasks, and added a number of extended codes for special f ...
, the ADM-3A did not use a microprocessor in its implementation, but instead used
TTL TTL may refer to: Photography * Through-the-lens metering, a camera feature * Zenit TTL, an SLR film camera named for its TTL metering capability Technology * Time to live, a computer data lifespan-limiting mechanism * Transistor–transistor lo ...
. It did, however, use RAM chips, rather than the Circulating Memory used by earlier terminals, such as the
Datapoint 3300 The DataPoint 3300 was the first computer terminal manufactured by Computer Terminal Corporation, later renamed Datapoint, announced in 1967 and shipping in 1969. Since this terminal was intended to replace a teleprinter such as those made by Telet ...
.


Legacy

The use of the
HJKL keys Arrow keys or cursor movement keys are buttons on a computer keyboard that are either programmed or designated to move the cursor (computers), cursor in a specified direction. The term "cursor movement key" is distinct from "arrow key" in that ...
for moving the cursor in the vi editor and its descendants originated from the ADM-3A,
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...
's
Teletype Model 33 The Teletype Model 33 is an electromechanical teleprinter designed for light-duty office use. It is less rugged and cost less than earlier Teletype machines. The Teletype Corporation introduced the Model 33 as a commercial product in 1963 after ...
replacement, just prior to the vi editor's creation; the cursor-movement arrows were printed on those four keys. The
Home key A home, or domicile, is a space used as a permanent or semi-permanent residence for one or many humans, and sometimes various companion animals. It is a fully or semi sheltered space and can have both interior and exterior aspects to it. H ...
and
tilde The tilde () or , is a grapheme with several uses. The name of the character came into English from Spanish, which in turn came from the Latin '' titulus'', meaning "title" or "superscription". Its primary use is as a diacritic (accent) in ...
label printed on the key may have additionally led to the establishment of the ''tilde'' character ("~") as the representation of the
home directory A home directory is a file system directory on a multi-user operating system containing files for a given user of the system. The specifics of the home directory (such as its name and location) are defined by the operating system involved; for ...
in many Unix shells. The
caret Caret is the name used familiarly for the character , provided on most QWERTY keyboards by typing . The symbol has a variety of uses in programming and mathematics. The name "caret" arose from its visual similarity to the original proofreade ...
character is also commonly used to represent the beginning of line or "home" position in
regular expression A regular expression (shortened as regex or regexp; sometimes referred to as rational expression) is a sequence of characters that specifies a search pattern in text. Usually such patterns are used by string-searching algorithms for "find" or ...
dialects. The , , , and labels printed on the , , , , and keys were a visual reference to the control characters , , , , and that were required to move the cursor left, down, up, right, and to the top/left corner (or "Home" position) of the terminal, respectively. The and functions were the standard
ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...
backspace Backspace () is the keyboard key that originally pushed the typewriter carriage one position backwards and in modern computer systems moves the display cursor one position backwards,"Backwards" means to the left for left-to-right languages. delete ...
and
line feed Newline (frequently called line ending, end of line (EOL), next line (NEL) or line break) is a control character or sequence of control characters in character encoding specifications such as ASCII, EBCDIC, Unicode, etc. This character, or a ...
respectively, but the interpretations of , , and were new to the ADM-3A. Also common with other terminals, produced an audible beep unless disabled via DIP switch and tabbed the cursor to the next tabstop, with tabstops fixed at each 8th character position. was used to clear the screen. Finally, the
control key In computing, a Control key is a modifier key which, when pressed in conjunction with another key, performs a special operation (for example, ); similar to the Shift key, the Control key rarely performs any function when pressed by itself. ...
was located above, not below, the
shift key The Shift key is a modifier key on a keyboard, used to type capital letters and other alternate "upper" characters. There are typically two shift keys, on the left and right sides of the row below the home row. The Shift key's name originated f ...
—in the same place where most modern PC keyboards put the Caps Lock key. Many standard Unix
key combination computing, a keyboard shortcut also known as hotkey is a series of one or several keys to quickly invoke a software program or perform a preprogrammed action. This action may be part of the standard functionality of the operating system or ...
s were designed with the QWERTY layout and the ADM-3A's original Ctrl key placement in mind. Many of those key combinations are still in use today, even on non-Unix operating systems. Seasoned computer users familiar with the original layout often claim that the different position of the Ctrl key on modern PC keyboard layouts makes the use of Ctrl key combinations more cumbersome. Solutions exist for many operating systems to switch around the Caps Lock and Ctrl keys in software, thus making the PC keyboard layout more closely resemble the ADM-3A's keyboard layout. The legacy of the ADM-3A's keyboard also lives on in Japan, where the local layout follows it almost exactly. Local Mac keyboard layouts even retain the ADM-3A's position of the Control key, transposing it with the Caps Lock key.


See also

*
Teletype Model 33 The Teletype Model 33 is an electromechanical teleprinter designed for light-duty office use. It is less rugged and cost less than earlier Teletype machines. The Teletype Corporation introduced the Model 33 as a commercial product in 1963 after ...


Notes


References


External links


Lear Siegler ADM-3A
on th
terminals wiki

Lear Siegler ADM 3A

Lear Siegler, Inc. (LSI) Terminal ADM3A
* * {{cite web , last1=Gangwere , first1=Morgan , title=Old tech: ADM-3A serial terminal, FreeBSD, and some fun. , url=https://quelab.net/6391/old-tech-adm-3a-serial-terminal/ , website=Quelab Computing output devices Character-oriented terminal