Sets the GdbusModemVoice instance for the D-Bus interface <link linkend="gdbus-interface-org-freedesktop-ModemManager1-Modem-Voice.
top_of_page">org.freedesktop.ModemManager1.Modem.Voice</link> on this.
| this | |
| interface_ |
A GdbusModemVoice or null to clear the interface. |