Glass Cockpits, COM Radio Channel Spacing
Flying above FL 195 in the Eurozone requires you to have a 8.33 kHz radio onboard. Eurocontrol: "In 1994 it was decided to introduce a further channel split from 25 to 8.33 kHz. Subsequently, 8.33 kHz was introduced above FL245 in the ICAO EUR Region from October 1999 and above FL195 from the 15 March 2007. At the time of writing, 8.33 kHz channels have been implemented in the airspace of over 20 ICAO EUR Region States."
Modern EFIS panels, like the G1000, will allow you to select these extra channels.
Above FL 195
8.33 kHz procedures quick reference guide
Excerpt from the document:
To request confirmation of 8.33 kHz capability : CONFIRM EIGHT POINT THREE THREE
To indicate 8.33 kHz capability : AFFIRM EIGHT POINT THREE THREE
To indicate lack of : NEGATIVE EIGHT POINT THREE THREE
To indicate that clearance prevents non-8.33 kHz equipped aircraft entering airspace of mandatory carriage : DUE EIGHT POINT THREE THREE REQUIREMENT
To continue reading see the pdf below: