can be assigned a function of choice. In addition, buttons on the steering wheel give access to various COMAND functions too and the large screen in the instrument cluster can display various COMAND related settings and information in addition to the main COMAND display. The model year 2009 W221 S-Class received an upgraded version, COMAND-APS 3.5 NTG. This includes improved Bluetooth support and split view (where the passenger watches a DVD while the driver sees other COMAND functions such as the navigation map on the same display). The new NTG3.5 system also features a new rights management provision to prevent the use of copied map update discs. This rights management function means it is not possible to upgrade NTG3 based vehicles to NTG3.5. COMAND-APS NTG4 The NTG4 system is a reduced cost version of NTG3 technology. It was first introduced when the W204 C-Class launched in 2007 and features a 7" screen, much smaller than the higher resolution, bigger 8" screen on the flagship W221. It is the first version of COMAND that supports the Mercedes Media Interface. Like NTG3, it stores maps on a hard disk and has a card reader for MP3 music. Amongst other implementation differences are the fact that in the W204 version the screen electrically folds in and out whereas in other incarnations it is fixed. The Mercedes SLS has COMAND NTG4 too. Unlike the NTG3 system, NTG4 did not support 7 character UK postcodes when first released (only 5 character postcodes), but some NTG4 units (e.g. those in the MY2010 W212 and up) have a firmware upgrade available from Mercedes dealers which does add 7 character UK postcodes. NTG4 is also used in Mercedes-Benz GLK-Class (X204). COMAND-APS NTG2.5 Somewhat confusingly, COMAND-APS NTG2.5 was introduced after NTG4, replacing COMAND in models previously fitted with NTG1 and NTG2 systems (apart from the W209 CLK as that model was replaced by the W207 E-Class coupe. The unit has a SD card reader in addition to the DVD drive. An optional DVD changer can replace the single drive. The Mercedes-Benz option code is 512 for the single drive unit and 527 for the unit with the optional DVD changer. Like NTG4 models, it supports the Media Interface. The unit also stores the navigation maps on an internal HDD which have some extra space for mp3 files. COMAND-APS NTG4.5 In late 2011, Mercedes starting fitting the new COMAND-APS NTG4.5