Worth getting the Bluetooth ID of whatever you're trying to pair with.
When you have the list to pair with in front of you, then you can match up.
For an intercom, e.g. Microavionics, it may only be discoverable for a short period after switch on. If it's on the master switch along with the Rosetta, the pairing period may be over before the boot up and connection to your device for control via the screen are complete.
You may therefore have to reboot the intercom or other device in order to see it.