to refer to the fact that the main COMAND unit for this first generation had a height of 2.5 DIN. This COMAND system had a cassette drive, a built-in CD drive for the navigation map discs, an FM/AM radio tuner, a 4-channel amplifier and external connectors to other systems. The European models used Tele Atlas map discs (CD). Towards the end of 1999, the system was upgraded to use the improved DX type navigation discs. COMAND 2.5 uses a D2B optical bus for connection to the external CD changer, the telephone system, the optional Bose surround sound system and the optional Linguatronic voice control system. The COMAND 2.5 unit was made by Bosch. COMAND 2.5 was an option on almost all models and denoted by Mercedes-Benz option code 352. COMAND 2.0/COMAND 2.0 MOPF The same COMAND 2.5 technology (with DX navigation maps) was next incorporated in a somewhat different form factor known as COMAND 2.0 (with "2.0" referring to the fact that this modified unit had a 2 DIN height), but with the cassette drive removed. These units were introduced on the W210 E-Class as rectangular units, later also in a more rounded form on amongst others the W203 and R230 models. From S-Class model year 2003, COMAND 2.5 was replaced by a widescreen version of COMAND 2.0 known as COMAND 2.0 MOPF. Note that COMAND 2.5, COMAND 2.0 and COMAND 2.0 MOPF are collectively referred to as "COMAND 2" systems (despite these being the first generation COMAND systems and, confusingly, despite the successor being known as COMAND-APS NTG1. COMAND-APS NTG1 This new generation of COMAND systems was introduced on the model year 2002 W211 E-class and is in fact a complete redesign. MOST replaces the D2B optical ring network. The Mercedes-Benz option code became 527 (although, confusingly, COMAND 2.0 MOPF was also given this option code). These new MOST based systems were given the name COMAND-APS to distinguish them from the older D2B systems. The NTG1 system further distinguished itself from earlier models by having DVD based navigation instead of the CD based COMAND 2. This allowed to carry a whole region (such as Europe) on a single disc. NTG1 systems were also able to play MP3 CDs/DVDs. COMAND-APS NTG2 The NTG2 evolution was a cheaper and more integrated version of COMAND-APS, having all core components in the single double DIN head unit instead of three separate components as