P/N 4941989 - Model B Keyboard Details & Specs

Provided by the ASK Keyboard Part Number Database

IBM 3276/3278 Final Keyboard Assembly with Num. Lock

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The IBM 3276 Control Unit Display Station and 3278 Display Station were the second generation of IBM 3270 Information Display System coaxial cable display terminals that first appeared in May 1977, succeeding the IBM 3275 and 3277 Display Stations respectively as standard terminals for IBM System/370 and compatible mainframes. The 3276 was a dual-purpose terminal like the 3275 that had an integrated control unit that could control up to seven additional display stations and printers for remote communications. The 3278 like the 3277 was just a terminal. Both the 3276 and 3278 were available in models with 960, 1920, 2560 or 3440 character displays. Joining them on 17th November 1977 was the IBM 3250 Graphics Display System and its IBM 3251 Display Station, which provided interactive graphics capabilities for CAD/CAM, architectural, simulation and mapping applications to System/370 and compatible mainframes. The IBM 8775 Display Terminal was an "intelligent" terminal that attached to the IBM 8100 Information System and was introduced alongside it in October 1978. The 8775 was a serial terminal and was notable for introducing multiple partitioning, which was a feature that allowed the user to define up to 8 rectangular separations for displayed data. Finally, the IBM 3279 Color Display Station was introduced in 1979 and was IBM's first colour terminal. The 3279 resembled the 8775 from the outside but was in fact a 3270 coaxial terminal that depending on the model had a 1920 or 2560 character display supporting 4 "base" colours or 7 "extended" colours.

The 87-key keyboard was the larger of the two "late 3270" keyboards. The 87-key keyboard was only available as a typewriter-style keyboard, so they were designed to facilitate both upper and lower-case character input and had a shift lock key like a 75-key typewriter keyboard but also had a dedicated keypad for rapid program function (PFxx) access. The base 87-key keyboard was available with ASCII Typewriter, EBCDIC Typewriter, EBCDIC Typewriter/APL or EBCDIC Typewriter/Text layouts. But for Japan, an 88-key version of the keyboard was available with (IBM World Trade Americas/Far East Corporation) Japanese English Typewriter, Japanese Katakana Typewriter or Japanese English/Japanese Katakana Typewriter/APL layouts. The 88-key keyboard gained the extra key in the top-left corner relative to the return key; to accommodate this, compared to the 87-key keyboard, the 88-key physical layout extended the width of the keys on the right side of the main alphanumeric key sections at the expense of the left side keys. A notable specific but technically still standard version of the 87/88-key keyboard was the Attribute Select Typewriter or Attribute Select Typewriter/APL Keyboard, which was intended for IBM 3270 applications that required adding highlighting attributes of data (3276/8/9) or adding colour (3279 only). It accordingly had various unique legends on its PFxx keypad for programmed symbols ("PSA" to "PSF"), extended highlighting ("a" with square background, radial lines or underscore) and extended colouring (solid rectangular blocks of colour). Specifically for IBM 8775s running Interactive Display Text Facility (IDTF, a licensed program that enabled the host terminal to be used in both data and text applications), the EBCDIC Typewriter/Text Entry and Edit Keyboard (feature code 4670) was introduced in June 1982 that sported narrow keypad keytops designed to hold a reversible text overlay to show what the keys do under normal conditions and during text entry and editing. The was also a range of RPQ keyboards available under special circumstances and custom orders such as 87-key keyboards with various numeric keypad layouts in place of the 12 dedicated PFxx keys and 88-key Hebrew and Cyrillic keyboards.

Late 3270 series keyboards characteristically had black cables with a right-angle male DB-25 plug and grounded screw bracket on its end, as well as an access panel in its palm rest that stored the host terminals' Problem Determination Guide for convenience. Late 3270 keyboards also had a solenoid inside that was used as a "keyboard clicker". In normal operation with their original host terminals, the clicker would engage as an audible confirmation for a registered key. The clicker could be toggled on or off with the bottom-right-most key of the left 4x2 key bank. If the clicker feature was turned off by the user, the solenoid could still be used for notifying the user when they try to press a key whilst the keyboard has been disabled by the terminal. Contrary to the common belief that this keyboard was the "3276 keyboard", cross-referencing with IBM parts catalogues reveals that IBMs 3276, 3278 and 3279 for the most part shared the same pool of keyboards and keyboard part numbers for this type.

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