this seems to be the relevant part of Asme (this is from 2007 i dont know if 2010 changes it):

"5.1.21 Emergency Operations and Signaling Devices
5.1.21.1 Emergency Signal and/or Communications. Each elevator shall be equipped with an alarm
button or switch in the car operating station and an
alarm device mounted in a location that shall be readily
available to a person who is normally situated in the
vicinity when the elevator is in use; or a means of voice
communication to a receiving station always attended
when the installation is in use. If the alarm device or
means of voice communication is normally activated by
utility power supply, it shall be backed up by a manual
or battery operated device. "

My reading is that the alarm bell is not required because we have a phone.

But the unclear part is, if there is a legacy alarm button as well as a new two-way communications phone (that works even when there is no power), does this mean that it's not a violation if the alarm bell button ceases working when the building loses power?