The Mercedes-Benz MOST Upgrade

Due to the complexity of the MOST Fiber Optic Network, upgrading older Mercedes vehicles to modern technology like Apple CarPlay or Bluetooth music streaming (A2DP) is often difficult and expensive.

The MOST optical loop is critical because it dictates sound signals in the vehicle’s audio system. Modifying it requires expensive hardware to translate the digital light signals into a usable format for newer technology.

Mercedes Infotainment and Audio System

Mercedes Bluetooth solutions depend on the age of your Mercedes vehicle and the type of Mercedes Phone system installed. Bluetooth can be added to most Mercedes vehicles allowing the use of a Bluetooth capable phone in your vehicle.

Mercedes Bluetooth for vehicles before late 2003 / early 2004:- Mercedes Benz vehicles supported two Mercedes phone systems – a fixed system that took a SIM card, and a system with a cradle.

Mercedes Bluetooth for vehicles from 2004 to 2009/2010:- Mercedes introduced the UHI (or MHI in North America) system where the phone cradle can be removed and replaced with a generic Bluetooth adapter.

Mercedes Bluetooth Phone 2009/2010 onward: – Many Mercedes have Bluetooth built in to the head unit, although the C & GLK before 2011 and the SLS won’t transfer contacts via Bluetooth without the optional Comfort Phone system and a Bluetooth adapter.

Which Bluetooth Adapter Should I use?

If you have a car with the fixed 6×10 cradle attached by a curly cable, you need to use the ViseeO MBU-3000 Bluetooth Adapter. It is the only integrated Bluetooth solution that will work without replacing the whole phone system

If you have a car with the UHI/MHI system:- if it is before mid 2004 you need to use the ViseeO MB-4 Bluetooth Adapter. You can not use the ViseeO MBU-3000 in a UHI 6310i cradle. If the car is post mid 2004 you can use the MB-4 or any Mercedes Bluetooth adapter such as the Mercedes HFP adapter or a phone specific cradle.

If you have a car with the Comfort Phone system, again to provide Bluetooth you can use a Viseeo MB-4 Bluetooth device, or a Mercedes HFP Bluetooth adapter, or any of the phone specific cradles.

You should note that most of the Mercedes phone specific cradles use Bluetooth to access the phone, so it can be in your pocket but when you plug it into the cradle it charges and uses the vehicles external aerial.

Mercedes MOST System

The MOST (Media Oriented System Transport) Optical Loop is a fiber optic network found in most 1998 – 2012 Mercedes-Benz cars to manage the communication between various infotainment and audio components.

The MOST Fiber Optical Loop

The MOST system operates using tiny fiber optic cables – a small, flexible glass tubes. These cables transmit information digitally via flashing red light signals for communication, replacing the traditional copper wires for data transfer.

• MOST System Architecture functions similars to a Christmas light ring or loop. If any part of the loop is interrupted, the circuit is broken the music and audio system will stop completely.

D2B to MOST

The Mercedes MOST system replaced the D2B fiber optic network, the D2B (Domestic Digital Bus), which was used in 1998 to 2003, such as the W210 E-Class. The MOST Era itself spanned roughly from 2002 to 2015.

COMAND Connected to the MOST System

The COMAND system connected to the MOST network sends the digital light signal.

The Audio Gateway (AGW): The AGW contains the radio, amplifier, and the MOST controller. The COMAND APS NTG 1 system specifically included the COMAND head unit, the Audio Gateway (AGW), and the navigation processor. Additional systems like the Harmon Kardon Audio System, CD changer are typically integrated into this same fiber optic ring.

Upgrading older Mercedes vehicles to modern technology like Apple CarPlay or Bluetooth music streaming (A2DP) is often difficult and expensive to make a new radio work with the existing factory amplifier (AGW), an additional MOST Decoder Box is required, parts costs for conversionare significantly higher, often between $500 and $800+.

The COMAND system is deeply integrated via MOST, a full head unit replacement carries a high risk of disabling critical vehicle functions and expensive factory options. It is therefore often recommended to use dedicated adapters that integrate Bluetooth through the original factory system, minimizing risk and preserving the vehicle’s resale value.

The MOST and COMAND in Mercedes Models

• W211 E-Class (COMAND NTG 1): Installing a navigation drive required extending the existing MOST optical loop to correctly integrate the navigation unit using specific labeled wires, which meant physically connecting the optical wires to integrate the new component into the “loop”.

• C219 CLS (COMAND NTG 1): This car uses a modular design where the AGW is in the trunk and connects to the dashboard via MOST, mandating the use of a MOST Decoder Box for modern upgrades.

• W221 S-Class (COMAND NTG 3/3.5): This system is deeply integrated via MOST and lacks native wireless audio streaming (A2DP), necessitating an upgrade, typically using a CarPlay/Android Auto Decoder Module integrated into the existing screen.

In essence, the MOST optical loop is critical because it dictates how signals—and therefore components—are structured within the vehicle’s audio system. Modifying or bypassing it requires sophisticated, expensive hardware to translate the digital light signals into a usable format for newer technology.

Examples of MOST in Mercedes Models

• W211 E-Class (COMAND NTG 1): required the MOST optical loop to correctly integrate the navigation unit physically connecting the optical wires to integrate the new component into the “loop”.

• C219 CLS (COMAND NTG 1): the AGW is in the trunk and connects to the dashboard via MOST, the MOST Decoder Box is needed for the upgrades.

• W221 S-Class (COMAND NTG 3/3.5): The S sedan lacks native wireless audio streaming (A2DP) requiring a CarPlay/Android Auto Decoder Module integrated into the existing screen.

The Mercedes MOST optical loop is critical because it dictates how signals—and therefore components—are structured within the vehicle’s audio system. Modifying or bypassing it requires sophisticated, expensive hardware to translate the digital light signals into a usable format for newer technology.

These models used the integrated COMAND APS (Navigation and Telematics Generation, or NTG) infotainment systems, which were complex, multi-component setups. 

COMAND (original CD based units)
W463	A463 820 10 89		Bosch		EU
W463	A463 820 15 89		Bosch		EU
W463	A463 820 16 89		Bosch		EU	ET4
W463	A463 820 17 89		Bosch		USA	ZU7/ZU8	Upto X145473, 31/10/2003
W463	A463 820 18 89		Bosch		USA	ZU7/ZU8	After 31/10/2003
							MY2001
W163	A163 820 14 89		Bosch		EU		MY2002-2004
W163	A163 820 36 89		Bosch		EU
W203	A203 820 91 89	A203 820 96 89	Bosch		EU		From 05/00
W203	A203 820 93 89	A203 820 23 42	Bosch		Japan
W203	A203 820 96 89		Bosch		EU		From 03/01
W203, W209, W463	A023 827 23 42		Bosch		Japan	W203 (352+498), W463: ZJ1
W203	A203 827 31 42		Bosch		USA
W203	A203 827 36 42	A203 827 52 42	Bosch		EU		Up to 9/02
W203	A203 827 37 42	A203 827 53 42	Bosch		USA
W203	A203 827 48 42		Bosch		EU		MY2004
W203	A203 827 52 42		Bosch		EU
W203	A203 827 53 42		Bosch		USA
W203, W463	A203 827 54 42		Bosch		Japan	W203 (352+498), W463: ZJ1
W208	A208 820 30 89	A208 820 37 89	Bosch		EU		From 06/99
W208	A208 820 31 89		Bosch		USA		Upto VIN F137202 or T041778
W208	A208 820 34 89	A208 820 40 89	Bosch		EU		From 06/00
W208	A208 820 35 89		Bosch		USA		MY2001
W208	A208 820 37 89		Bosch		EU		From 12/99
W208	A208 820 38 89		Bosch		USA		MY2000
W208	A208 820 40 89		Bosch		EU		From 07/00
W208	A208 820 44 89		Bosch		EU		From 08/01
W210	A210 820 48 89		Bosch		EU		MY2000	No CANBUS
W210	A210 820 49 89		Bosch		USA		MY2000	No CANBUS
W210	A210 820 51 89		Bosch		EU		From 06/00 MY2001
W210	A210 820 52 89		Bosch		USA		From 06/00 MY2001
W210	A210 820 54 89		Bosch	7612001470	EU		From 07/00 MY2001
W210	A210 820 55 89		Bosch		USA		From 07/00 MY2001
W210	A210 820 56 89		Bosch		EU		From 08/01 MY2002
W220	A220 820 03 89		Bosch		EU		Upto 10/6/1999
W220	A220 820 04 89		Bosch		USA		Upto 8/6/1999
W220	A220 820 34 89		Bosch		EU		From 8/9/99 to 30/6/00	MY2000
W220	A220 820 35 89		Bosch		USA		From 8/9/99 to 30/6/00	MY2000
W220	A220 820 37 89		Bosch		EU		From 11/8/00 to 30/6/01	MY2001
W220	A220 820 40 89		Bosch		EU		From 30/6/01 to 25/9/01	MY2002
W220	A220 820 41 89		Bosch		USA		From 30/6/01 to 25/9/01	MY2002
W220	A220 820 46 89		Bosch		EU		From 10/6/99 to 8/9/99
W220	A220 820 47 89		Bosch		USA		From 8/6/99 to 8/9/99
W220	A220 820 48 89		Bosch		EU		From 30/6/00 to 11/8/00	MY2001
W220	A220 820 49 89		Bosch		USA		From 30/6/00 to 30/6/01	MY2001
W220	A220 820 71 26	A220 820 34 89	Bosch		EU		From 8/9/99
W220	A220 820 72 26	A220 820 35 89	Bosch		USA		From 8/9/99
W220	A220 820 04 42		Bosch		EU		From 25/9/01 to 1/9/02	MY2002
W220	A220 820 05 42		Bosch		USA		From 25/9/01 to 1/9/02	MY2002
W220	A220 827 14 42		Bosch	7612500042	EU		Upto 30/9/2003	MY2003 Widescreen – NO NAVIGATION UNIT
W220	A220 870 58 89		Bosch	7612500400	EU	530	Fr. Ch. A265054 30/9/2002 excep MY02	MY2003 Widescreen
W220	A220 820 59 89		Bosch		USA	530	Fr. Ch. A265054 30/9/2002 excep MY02	MY2003 Widescreen
W220	A220 820 60 80		Bosch		JAPAN	529	Fr. Ch. A265054 30/9/2002 except MY02 to A4122665 14/1/04	MY2003 Widescreen
R230	A230 820 05 89				EU		Upto 31/7/02 Ch. F026959
R230	A230 820 06 89				USA		Upto 29/10/03 Ch. F069434	MY2003
R230	A230 820 23 89				JAPAN		Upto 10/9/02 Ch. F032753
R230	A230 820 25 89				EU		From 31/7/02 to 28/5/04	MY2003 & 2004
R230	A230 820 28 89				USA		From 31/10/2003	MY2004
R230	A230 820 29 89				JAPAN		From 10/9/2002
COMAND APS (DVD BASED)
W211	A211 827 23 42	A211 827 61 42			ECE	526/527		Nav separate, No Video
W211	A211 827 61 42	A211 827 67 42			ECE	526/527	Classic	Nav separate, No Video
W211	A211 827 67 42	A211 870 00 89			ECE	526/527		Nav separate, No Video
W211,W219	A211 870 00 89	A211 820 21 97	Becker	BE 7039	ECE	526/527	W211: Upto Ch. A791426 11/4/2005, X185860	Nav separate, NO video interface
W211,W219	A211 820 21 97		Becker	BE 7039	ECE	(526/527+(860,861,863)	W219: Upto 8/9/05	Nav separate, with Video
W211	A211 827 24 42	A211 827 62 42	Becker	BE 6061	ECE	(526,527)+(954,955)	Elegance/Avantgarde	Nav is separate	contains A211 827 01 57 002 aswell
W211	A211 827 62 42	A211 827 68 42	Becker	BE 6061	ECE	(526,527)+(954,955)	Elegance/Avantgarde	Nav is separate
W211	A211 827 68 42		Becker	BE7039	ECE	(526,527)+(954,955)	Elegance/Avantgarde	Nav is separate
W211	A211 870 01 89				ECE			Not in EPC (on update disk)
W211	A211 820 45 89		Becker	BE7036
W211	A211 820 22 97	A211 870 46 89	Becker	BE7023	ECE	(526,527)+(860,861,863)		Head unit (nav separate) – with video
W211	A211 870 46 89				ECE	(526,527)+(860,861,863)		Head unit (nav separate) – with video
W219	A211 870 47 89				ECE	526/527	W219: Fr 8/9/2005
W211	A211 827 25 42	A211 827 63 42			USA	(528.530),(_,954,955)		Nav is separate
W211	A211 827 63 42		Becker	BE7024	USA	528/530	Upto Ch. A635991 30/6/2004, X170336 30/6/2004	Nav is separate	contains A211 827 06 77 001 aswell
W211,W219	A211 870 02 89	A211 820 23 97	Becker	BE7024	USA	(528,530)+805	MY2005	Nav is separate, NO VIDEO Interface
W211,W219	A211 820 23 97	A211 920 27 97			USA	528/530	Up to Ch. A866659 29/7/2005, X192062 17/8/2005	Nav is separate
W211,W219	A211 820 27 97				USA	528/530	From A445776 30/9/2003 except MY04, X123273 30/1/2004 except MY04	Nav is separate
W211,W219	A211 870 07 89	A211 870 30 89			JAPAN	529	W211: Upto Ch. A783569 16/3/2005, X186582 25/4/2005. W215: Upto A023325 16/3/05
W211,W219	A211 870 30 89				JAPAN	529
R171	A171 820 20 89	A171 820 38 89			JAPAN	529	Upto Ch. F011764 29/4/2005
R171	A171 820 38 89				JAPAN	529
R171	A171 820 16 89	A171 820 29 89			ECE	527
R171	A171 820 29 89	A171 820 33 89			ECE	527	Upto Ch. F064987 28/2/2005
R171	A171 820 33 89	A171 820 42 89			ECE	527	Up to 31/08/2005
R171	A171 820 42 89				ECE	527
R171	A171 820 19 89	A171 820 30 89			USA	530
R171	A171 820 30 89	A171 820 43 89			USA	530/528	Upto Ch. F016251 31/5/2004	Nav is separate
R171	A171 820 43 89				USA	530/528		Nav is separate
R230	A230 820 36 89	A230 820 42 89			USA	530		Nav is separate
R230	A230 820 42 89	A230 820 44 89	Siemens		USA	530		Nav is separate
R230	A230 820 44 89	A230 820 48 89	Siemens		USA	530		Nav is separate
R230	A230 820 48 89	A230 820 51 89	Siemens		USA	530		Nav is separate
R230	A230 820 51 89		Siemens		USA	530	Upto F109634 31/5/05 except MY06	Nav is separate
R230	A230 820 46 89	A230 820 54 89	Siemens		USA	530	Fr. Ch. F099797 13/1/05 except MY06	Nav is separate
R230	A230 820 54 89		Siemens		USA	530	Fr. Ch. F099797 13/1/05 except MY05	Nav is separate
R230	A230 820 35 89	A230 820 41 89			ECE	805	From Ch F071048 14/1/04	Nav is separate
R230	A230 820 41 89	A230 820 43 89	Siemens		ECE			Nav is separate
R230	A230 820 43 89				ECE		Upto Ch. F099483 30/11/2004	Nav is separate
R230	A230 820 47 89		Siemens		ECE		From Ch. F099484, 30/11/2004	Nav separate, Contains AGW A230 827 06 57 and A230 445 0960
R230	A230 820 50 89		Siemens		ECE		Ch F105848 31/3/05 to F109634 31/5/05 except MY06	Nav is separate
R230	A230 820 45 89	A230 820 53 89	Siemens			526/527	Fr. Ch. F099797 13/1/05 except MY05	Nav is separate
R230	A230 820 53 89					526/527	Fr. Ch. F099797 13/1/05 except MY05	Nav is separate
W220	A220 870 21 89	A220 870 23 89	Siemens		ECE		W220: Fr. Ch. A441008 30/6/04	Nav is separate
W220	A220 870 23 89	A220 870 33 89	Siemens		ECE		W220: A441008 30/6/04 to A457770 1/12/04	Nav is separate, contains AGW A220 827 0657
W220	A220 870 33 89	A220 870 37 89	Siemens		ECE		W220: A457771 1/12/04 to 4/4/2005	Nav is separate
W220	A220 870 37 89		Siemens		ECE		W220: Fr Ch. A457771 1/12/04	Nav is separate
W220	A220 820 60 89	A220 820 11 89			JAPAN	529	W220: A265054 30/9/02 (except MY02) to A412265 14/1/04	Nav is separate
W220	A220 820 11 89	A220 820 31 89			JAPAN	529	W220: Fr. Ch. A412266 14/1/04	Nav is separate
W220	A220 820 31 89				JAPAN	529	W220: Fr. Ch. A412266 14/1/04	Nav is separate
W220	A220 827 41 42		Siemens		ECE		W220: Fr Ch. A392659 30/9/03	Nav separate, Contains Audio G/W A220 827 02 57
W220	A220 827 42 42		Siemens		USA	530	W220: Fr. Ch. 368544 24/4/03 to A441007 30/6/04	Nav Separate, Contains Audio G/W
W220	A220 870 22 89		Siemens		USA	530	W220: Ch. A411833 22/1/04 to A451232 13/9/04	Nav is separate
W220	A220 870 24 89		Siemens		USA	530	W220: Ch A451233 13/9/04 to A457770 1/12/04	Nav is separate
W220	A220 870 34 89		Siemens		USA	530	W220: From Ch. A457771 1/12/04	Nav is separate
W220	A220 870 38 89		Siemens		USA	530		Nav is separate
W220	A220 870 10 89				USA	530+805	Fr: Ch 385117 31/7/03 to A411832 22/1/04	How come 805 MY05 – epc prob. wrong
W169	A169 820 39 89	A169 820 51 89			ECE	527	Upto Ch. J070662 14/12/2004
W169/W245	A169 820 51 89		Becker	BE6093	ECE	527
W169/W245	A169 820 60 89				ECE	527+807	MY2007 (AEJ 06/1/M/X)
W169/W245	A169 820 26 89	A169 820 58 89			JAPAN	529	Upto Ch. J-12994 10/8/2005
W169/W245	A169 820 58 89				JAPAN	529
W245	A169 820 41 89				USA	530
W245	A169 820 79 89				USA	530+807	MY2007 (AEJ 06/1/M/X)
W164/X164	A164 820 09 79				ECE	527
W164	A164 820 03 79	A164 820 06 79			USA	528	Up to 01/08/2005	No Navigation
W164	A164 820 06 79				USA	528		No Navigation
W164	A164 820 07 79				USA	530
W164	A164 820 05 79	A164 820 81 89			JAPAN	529
W164	A164 820 81 89	A164 870 09 89			JAPAN	529
W164/X164	A164 870 09 89				JAPAN	529
W203	A203 827 33 42	A203 870 42 89			JAPAN		Up to 30/11/2005
W203	A203 870 42 89				JAPAN
W203	A203 827 42 42	A203 870 10 89			ECE
W203	A203 870 10 89	A203 870 20 89			ECE		Upto Ch. A761837 4/12/2005, F666188 7/12/2004, R183645 18/1/2005
W203	A203 870 20 89	A203 870 35 89			ECE		Upto Ch. R180076 7/1/2005, F666188 7/12/2004, A745748 29/10/2004
W203	A203 870 35 89		Becker	BE6096	ECE			contains A203 827 00 62
W203	A203 827 43 42	A203 870 29 89			USA
W203	A203 870 29 89	A203 870 41 89			USA		Upto Ch. R153498 30/6/2004, A816056 29/4/2005, F714500 1/5/2005
W203	A203 870 41 89				USA		Upto Ch A833518 30/6/2005, F736840 30/6/2005, R200762 29/9/2005
W203	A203 870 11 89				USA		MY06 – From Ch A833519, 30/6/2005, F736841 30/6/2005, R200763, 29/9/2005
W209	A209 820 32 89	A209 870 08 89			JAPAN	529
W209	A209 870 08 89				JAPAN	529
W209	A209 820 30 89	A209 820 38 89	Becker	BE6099	ECE	527+805	COMAND-APS 1st installed in MY05	with navi & 203 827 00 62 nav built in
W209	A209 820 38 89	A209 820 45 89	Becker	BE6096/6099	ECE	527	Upto Ch F151428 9/12/04	with navi & 203 827 00 62 nav built in
W209	A209 820 45 89	A209 820 54 89			ECE	527
W209	A209 820 54 89		Becker	BE6096 / 609	ECE	527		with audio-hw 203 827 00 62 built in
W240	A240 820 61 89		Becker		ECE
W240	A240 820 66 89		Becker		ECE
W240	A240 820 75 89		Becker		ECE
W240	A240 820 62 89		Becker		USA
W240	A240 820 67 89		Becker		USA
W240	A240 820 76 89		Becker		USA
Navigation Unit
S/E	A211 820 06 85		Becker	6059	ECE/USA	527/530	W220: Upto A368543 24/4/03
S	A220 820 59 85	A220 820 60 85			ECE/USA	527/530	W220: From A368544 24/4/03
Any	A220 820 60 85	A220 870 35 89			ECE/USA	527/530	W220: From A368544 24/4/03
Any	A220 870 35 89		Becker	6059	ECE/USA	527/530	W220: From A368544 24/4/03
AUDIO Gateways
W203	A203 827 00 62						Used with Audio 20/Audio-50APS
W211	A211 870 25 89		Becker	BE6032
W211	A211 827 41 42		Becker	BE6030
R230	A230 827 00 57	A230 827 02 57	Siemens		ECE		AEJ05 (s/w type V3)
R230	A230 827 02 57	A230 827 06 57	Siemens		ECE		AEJ05 (s/w type V3)	Upto Ch. F099483 30/11/2004
R230	A230 827 04 57		Siemens		ECE		AEJ05 (s/w type V4)
R230	A230 827 06 57		Siemens		ECE		AEJ05 (s/w type V4)
R230	A230 827 06 57		Siemens		ECE		AEJ05 (s/w type V4)
R230	A230 827 08 57		Siemens		ECE		AEJ05 (s/w type V4)
R230	A230 827 10 57		Siemens		ECE		AEJ05 (s/w type V4)
R230	A230 827 12 57		Siemens		ECE		AEJ05 (s/w type V4)
R230	A230 827 01 57	A230 827 03 57	Siemens		USA		AEJ05 (s/w type V3)
R230	A230 827 03 57	A230 827 07 57	Siemens		USA		AEJ05 (s/w type V3)	Upto Ch. F099483 30/11/2004
R230	A230 827 05 57		Siemens		USA		AEJ05 (s/w type V4)
R230	A230 827 07 57		Siemens		USA		AEJ05 (s/w type V4)
R230	A230 827 09 57		Siemens		USA		AEJ05 (s/w type V4)
R230	A230 827 11 57		Siemens		USA		AEJ05 (s/w type V4)
R230	A230 827 13 57		Siemens		USA		AEJ05 (s/w type V4)
W220	A220 827 02 57		Siemens		ECE		AEJ04 (s/w type V1)	From update CD
W220	A220 827 04 57		Siemens		ECE		AEJ04 (s/w type V1)	From update CD
W220	A220 827 06 57		Siemens		ECE		AEJ04 (s/w type V1)	From update CD
W220	A220 827 08 57		Siemens		ECE		AEJ04 (s/w type V2)	From update CD
W220	A220 827 10 57		Siemens		ECE		AEJ04 (s/w type V2)	From update CD
W220	A220 827 12 57		Siemens		ECE		AEJ04 (s/w type V2)	From update CD
W220	A220 827 03 57		Siemens		USA		AEJ04 (s/w type V1)	From update CD
W220	A220 827 05 57		Siemens		USA		AEJ04 (s/w type V1)	From update CD
W220	A220 827 07 57		Siemens		USA		AEJ04 (s/w type V1)	From update CD
W220	A220 827 19 57		Siemens		USA		AEJ04 (s/w type V2)	From update CD
W220	A220 827 11 57		Siemens		USA		AEJ04 (s/w type V2)	From update CD
W220	A220 827 13 57		Siemens		USA		AEJ04 (s/w type V2)	From update CD