How to use bluetoothctl effectively?

When using bluetoothctl, it seems necessary to run the command scan on before it will connect to a low energy (IoT) device. I know the MAC of the device, but attempting to connect to it directly always fails with a Device xx:xx:xx not available error message. Within 1-3 seconds of turning on scan on , it becomes possible to connect to the device. But as soon as scan off is run, the device immediately disconnects. While running, I receive an onslaught of [CHG] Device xx:xx:xx and [NEW] Device xx:xx:xx messages. I work in an office building with apparently dozens to hundreds of devices occasiona

Question by John O on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.