The Wikipedia has some information about the keyboard:
In Michael Bloomberg's 1997 autobiography, in a chapter titled "Computers for Virgins", he explained how the design of the terminal was slightly different from the standard IBM PC keyboard layout that was popular at that time. The keyboard layout was designed for traders and other market makers who had no prior computer experience. While the look and feel of the Bloomberg keyboard is very similar to the standard computer keyboard, there are several enhancements that help users navigate through the system, from the idea for a user friendly system when originally designed in the early 1980s.
Commands for the keyboard are commonly referred to inside angle brackets. The keys were replaced from the technical name (i.e. F10) and the then standard beige color, opting for a user friendly name and a memorable color, in this example for a lookup on an Index with a yellow key. Another example, the "Esc" for most computer keyboards is referred to as red colored <CANCEL> key in the Bloomberg system, with the red to catch one's eye to stop a task. The "Enter" key is referred to as <GO> with a green color, deriving from the Monopoly game board, by passing "Go" and collecting $200 in a hope that the user could make money on the information he would find (hence the green key.)
Crucially, the Bloomberg keyboard includes a unique <MENU> key, which serves a similar function to the "back" button in an internet browser.
The yellow hot keys along the top of the keyboard are used to enter market sectors, and must be used to allow the terminal to correctly identify a security.
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