: ModemManager Reference Manual

## Listing available modems

The D-Bus name `org.freedesktop.ModemManager1` on the system bus is the new name used by the ModemManager 1.0 daemon, and it implements several standard DBus interfaces, including the new `org.freedesktop.DBus.ObjectManager` interface, which allows to list available modem objects and get notifications where new ones are added or when existing ones are removed. There are therefore neither a custom method to enumerate devices as in the old 0.6 interface, nor custom signals to notify about added or removed modems.

Modems which are found but are not usable will be flagged with a `MM_MODEM_STATE_FAILED` state in the `State` property, and a more detailed reason about the failure will be given in the `StateFailedReason` property. The most common case of failure is to have the SIM missing in a modem which requires one for operation.