Ubuntu phone aka a remote-controlled microphone
touch /userdata/.writable_image reboot device ssh phablet@IP address sudo -s apt-get install url-dispatcher-tool ^d url-dispatcher tel:+3112345678
walk to phone, unlock, select sim card and hit dial
An alternative way would be:
ssh phablet@IP address /usr/share/ofono/scripts/dial-number +3112345678 /usr/share/ofono/scripts/answer-calls
This is one way to create a remote listening device (there are probably easier alternatives):
Hide a Ubuntu phone somewhere at your adversary.
ssh to the device
dial the phone (from an undisclosed phone)
pick up the call
/usr/share/ofono/scripts/answer-calls [ /ril_1 ] [ /ril_1/voicecall01 ] incoming [ /ril_0 ]
and start listening, until the device is discovered or the battery runs out.