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The IBM 3270 Information Display System is a family of block-oriented
computer terminals and control units introduced by IBM in May 1971.
Designed to succeed the earlier IBM 2260, the 3270 was developed to
efficiently interface with IBM mainframes, such as the System/360 and
System/370, by minimizing the frequency of I/O interrupts to the host
processor. Unlike asynchronous terminals that transmit data character-
by-character, the 3270 system utilizes a local buffer and transmits
only modified data fields in a single block when an attention key is
pressed.<ref>{{cite web
| url = http://www.bitsavers.org/pdf/ibm/3270/GA27-2739-1_An_Introduction_to_the_IBM_3270_Information_Display_System_May71.pdf
| title = An Introduction to the IBM 3270 Information Display System
| author = IBM Corporation
| date = May 1971
| publisher = Bitsavers.org
| accessdate = February 27, 2026
}}</ref>

The system's architecture relies on cluster controllers, such as the
IBM 3271 or 3272, which manage the communications between multiple
display stations and the host. Connection to the controller is
typically achieved via 93-ohm RG-62 coaxial cable. The 3270 data stream
allows the host to define specific fields on the screen with distinct
attributes, including protected (read-only), numeric-only entry, and
high intensity.<ref>{{cite web
| url = http://www.bitsavers.org/pdf/ibm/3270/GA27-2749-0_IBM_3270_Information_Display_System_Component_Description_May71.pdf
| title = IBM 3270 Information Display System Component Description
| author = IBM Corporation
| date = May 1971
| publisher = Bitsavers.org
| accessdate = February 27, 2026
}}</ref>

== IBM 3270 Family Terminals ==
The following terminals comprise the official IBM 3270 product line:
* [[IBM 3275]] Standalone Display Station (Models 1 and 2)
* [[IBM 3277]] Display Station (Models 1 and 2)
* [[IBM 3276]] Control Unit Display Station
* [[IBM 3278]] Display Station (Models 1, 2, 3, 4, and 5)
* [[IBM 3279]] Color Display Station
* [[IBM 3178]] Display Station
* [[IBM 3179]] Color Display Station
* [[IBM 3180]] Display Station
* [[IBM 3191]] Display Station
* [[IBM 3192]] Color Display Station
* [[IBM 3194]] Color Display Station
* [[IBM 3290]] Information Panel (Gas Plasma Display)

== Compatible Terminals ==
The dominance of the 3270 architecture led to the creation of a large
market for plug-compatible terminals from third-party manufacturers.
These devices were designed to emulate IBM hardware while often
offering additional features or lower pricing.

Manufacturers and models included:
* [[ADDS Viewpoint 78]]
* '''AT&T Teletype''': [[AT&amp;T 4540|4540]] and [[AT&amp;T 5540|5540]] series, [[AT&amp;T 6578|6578]] terminal
* '''Beehive International''': [[Beehive DM3270|DM3270]] and [[Beehive ATL-078|ATL-078]]
* [[Datamedia Excel 3270-S]]
* [[ICC System 400]]
* '''ITT Courier''': 270 and 9000 series terminals
* '''Lee Data''': [[Lee Data 1191|Model 1191]], and [[Lee Data 1192|Model 1192]] "all-in-one" terminal
* '''Memorex Telex''': [[Memorex 1377|1377]] and [[Memorex 2078|2078]] series display stations
* '''Raytheon Data Systems''': [[Raytheon PTS-100|PTS-100]] and [[Raytheon PTS-2000|PTS-2000]]

{{References}}

[[Category:IBM|3270 Information Display System]]
[[Category:CRT]]