Has the '5' key on the numeric keypad ever had an alternate function in hardware?

Solution 1:

I looked at my library of images, and found two examples that seem relevant.

1:

that seems to be using the numeric 5 for… something related to cursor manipulation. I am not sure what it does.

2:

with a trackpad built into it. It seems that the numeric keypad doubles as hardware “mouse keys”, with extra arrow keys and 5 labeled as “Click.”

Solution 2:

The special function "printed" on the '5' on the numeric key pad was (and still often is) a mark to recognize that key with your fingers without looking at it.

Solution 3:

There is an odd variant of USB numeric keypad, VZTEC VZ-UK2151, which had numeric key '5' as function key 'Tab'. See the following screenshot (bottom-left: enlarged image of the key) as proof.

That 5 key works same as Tab key. It also works in GNU/Linux, even not listed as supported operating system besides Windows and Mac OS X. The product was likely manufactured in 2011.

Solution 4:

This should shed some light, hopefully.

The OMNI key on old Northgate Ultra keyboards had the same function as the 5 on the numeric keypad when numlock was OFF. I assume the scan codes are the same.

In Northgate's manual (from April 1992) on page 19 it indicates that OMNI key was used in Word Perfect (for DOS). So maybe we're a little closer to knowing how to make that work.