Editing IBM Beam Spring Keyboards (section)

==3604==

<gallery widths="250" heights="180" caption="IBM 3604 Keyboard Display">
File:3604-74key.jpg|Diagram from an IBM guide showing the layout of the 74-key alphanumeric layout
File:3604 keyboard.jpg|3604 94 key extended alphanumeric keyboard
File:3604 numeric keypad 2.PNG|3604 with 30 key numeric keypad keyboard
</gallery>

Launched in 1973, the IBM 3604 Keyboard Display keyboards were part of the IBM 3600 Financial Communication System, a set of terminals and printers for bank tellers, and the networking equipment required to interface them with an IBM mainframe. The 3604 keyboard displays were the 3600's terminals, there were six models of which Models 1 - 4 featured beam spring keyboards (Models 5 and 6 used smaller keys which, at least in later production examples, used rubber dome switches). Model 1 was a compact unit which could be equipped with one of three keyboard options:

*A 30-key Numeric Keypad, which featured a 15-key numeric keypad, and another 15-key block whose functionality was determined by the system software.
*A Data Entry layout, which was based on the Numeric Keypad.
*A 45-key Extended Numeric Keypad, which added another 15-key programmable function block to the keyboard.

Models 2 - 4 were larger units which differed by screen size. There were two more keyboard options available in addition to the ones available for the Model 1:

*A 74-key Alphanumeric layout, which featured an alphanumeric keypad with the same physical alphanumeric keypad layout as that on the 3277 78-key terminals. To the right of that was a numeric keypad and a number of programmable function keys. It is perhaps interesting to note that if one takes this layout, removes the Reset and Enter keys, replaces the Return and Back Tab keys with an ISO-style return, replaces the Tab and Lock key with a single L-shaped key the result is quite similar to the physical key arrangement of the later IBM 5100.
*A 94-key Extended Alphanumeric layout, which added an additional 20 programmable function keys to the standard Alphanumeric layout.

The 3604 was replaced by the IBM 4704 which was launched in 1981. The 4704's Model F keyboard options have layouts inspired by the 3604.