The short answer
Elevator emergency phones must provide two-way communication to a monitored location, remain operable during a power failure, and be tested regularly. A managed POTS box meets those expectations by supplying analog dial tone with internal battery backup and continuous line supervision, with test documentation for the inspector.
What the code is actually asking for
ASME A17.1 and its local adoptions focus on outcomes: a passenger trapped in a cab must be able to reach a person who can send help, that communication must work when the building loses power, and the arrangement must be verified periodically.
Nothing in that outcome requires copper. Copper was simply the only technology that satisfied it when the requirement was written.
The four things an inspector checks
- Two-way voice communication is established with a responder
- The call reaches a location that is staffed or monitored at all times
- The system operates during loss of building power
- There is documentation showing periodic testing
How managed transport satisfies each
| Requirement | How it is met |
|---|---|
| Two-way voice | Existing cab phone and dialer are unchanged; the box supplies real dial tone |
| Monitored destination | Ported number keeps dialing the same monitoring center |
| Power failure operation | Internal battery sized for a full working day at load |
| Testing records | Test-call logs plus continuous supervision history retained per line |
Where projects go wrong
- Using a consumer ATA with no battery and no supervision
- Forgetting to port the number, so cab labels and monitoring records go stale
- Cutting over without a live test call to the monitoring center
- No written record, so the next annual inspection restarts the argument
Talk to the AHJ early
Local amendments vary. A five-minute conversation with the authority having jurisdiction before the cutover, with the device documentation in hand, prevents a failed inspection after it.
Last updated 2026-08-20.