When you say emergency all-call what happens? Is this a page over the phones?
It dials into our paging system. Then from there it can enter codes to page specific areas.
So if you were to hit the normal page button which just dials the paging system and then enter the code, no echo.
When having the speed dial or have also tested with system speed dial adding pauses, that dials both the paging system and the code then you get the echo. Have tried multiple areas using system speed dials and all echo when entering both the paging system and the code with the same speed dial.