https://en.wikipedia.org/wiki/Olivetti_M24
I really like that light blue almost turquoise printing on these keycaps. Like the Model F XT this keyboard has a lot of stepped keycaps with LED cutouts in this case.The system was sold in the United States under its original name by Docutel/Olivetti of Dallas.AT&T and Xerox bought rights to rebadge the system as the AT&T PC 6300 and the Xerox 6060 series, respectively. AT&T owned 25% of Olivetti around this time. The AT&T 6300, launched in June 1984, was AT&T's first attempt to compete in the PC compatible market.
Next to the ANK 25-102 the ANK 2463 is slightly more compact just like an XT keyboard usually.
This keyboard consists of five parts; Top and bottom case, metal plate with switch housings, PCB and a smaller metal plate covering only the area for the plastic standoffs.
Note it reads " /19 IBM 27349" on a small sticker on the metal plate.
The spacebar is massive at 10 units stabilized by a bar and two additional springs.
This keyboard is from 1986, according to wikipedia the M24 was discontinued in 1987.
This keyboard uses the plate mounted tactile Olivetti dome with slider switch, the switch is a discrete unit that is held in the coutouts on the plate by a tiny snap-in mechanism. Very servicable like Nixdorf magnetic switches.
The switch consists of housing, slider, spring, insert and rubber mat that fits over the bottom part of the switch housing.
AT&T and Xerox also used this switch in some of their keyboards. I'm not sure if the color of the slider has any meaning, I have only seen white ones and these red ones. Some of the sliders on this keyboard have a paler lighter almost pink color, but all the switches feel the same. You can read more about the Olivetti dome with slider switch here:
wiki/Olivetti_dome_with_slider
The color of the printing is one of my favorite ever:
Friendly and compatible...