"The early Mac keyboards used the same RJ11 connector as a telephone handset. However, the wiring was reversed, so you couldn’t replace the keyboard cable with a handset cable."

If I remember correctly, telephone connectors split the twisted pairs down the middle of the connector. I can't remember the colors but for 6 pin it was something like.

   r+ b- g+ (middle) g- b+ r-

4 pin would be the middle 4 wires.

Shouldn't reversing the wires get an identical wiring?

8 pin ethernet started the same way, however they found the spread at the end was getting to large for the differental signal quality needed. so it goes middle two pars are spread with a pair at each side.

    br+ br- gr+ bl- bl+ gr- or+ or-

> Apple no longer uses a phone connector for its keyboard

I think Lightning has to qualify as a ”phone” connector, though in a different way. https://support.apple.com/en-us/112037