ironbutt57 Eckhard..I suspect you are referring to the "alt hold button"?..equivalent of "push to level" on the Airbus...by pushing in the VS/FPA selector
As far as I know:
Boeing MCP: ALT button will stop climb or descent and level at the altitude that the button was pressed. In other words, an overshoot and then regaining of the altitude.
Airbus FCU: push to level off feature of VS knob has similar effect except the climb descent will stop at whichever altitude is reached when VS is 0. In other words, no regaining of the altitude when the button was pushed.
Airbus FCU: A320 family may have an ALT button or an EXP button mounted in the same space on the panel.
Don't know how the ALT button works as my A319/320/321s don't have it.
EXP button works as previously described.
In my original post I was trying to point out that not all Airbii have an ALT button, although some do. I was answering a previous post which suggested that none had the ALT button.
Confused? I am!