It is my understanding that it applies to both. If you have ATM's in service that can be upgraded to include voice guidance then you should upgrade those machines.--unless you can prove "undue burden".
In our case, we have only a few ATMs. Some are upgradeable and some are not. Some of our machines will not be serviceable in the next couple of years.
Therefore we have put the upgrades and replacements on a schedule to be accomplished over a period of time.
_________________________
Always learning something new...