Connection & disconnection: ModemManager Reference Manual

## Connection & disconnection

Connecting the Modem is done through the Bearer objects. Once such an object is created, the user can request to get the given bearer connected.

Broadband Modems will usually create Broadband Bearers. This kind of bearers can run either the CDMA connection sequence (if the modem has CDMA capabilities) or the 3GPP connection sequence (if the modem has 3GPP capabilities). For the special case of mixed 3GPP+CDMA modems, it is assumed that the plugin implementation needs to decide how the connection gets done. By default, anyway, the 3GPP sequence is used in this case.

Modems which are both LTE (3GPP) and CDMA can hand over from LTE to CDMA transparently and automatically when no LTE network is available, even keeping the same IP address. When this happens, the modem will get notified about the access technology change, and ModemManager will update that information.