rSAP working with Nexus 4 (at last!) and some alternatives

Discussions about rSAP and general Bluetooth compatibility of the Mercedes-Benz Bluetooth SAP telephone module
Post Reply
Posts: 2
Joined: Thu Feb 19, 2015 7:32 pm

rSAP working with Nexus 4 (at last!) and some alternatives

Post by adammitch » Thu Feb 19, 2015 8:49 pm

Hi All,

Just thought I would give an account of my issues and solutions and to say a thank you to the Dev for making the app.

I've also included some alternatives (near the bottom of my comments) to using rSAP if you can't live with the inherent disadvantages of rSAP.

So my original set up:

Handset: Google/LG Nexus 4 (mako)
O/S: Android 5.0 Lollipop, unrooted, stock
Car: Mercedes R Class (2007)
Headunit: Comand NTG 1
COMAND-NTG1.jpg (66.07 KiB) Viewed 3468 times
Bluetooth adapter: Mercedes Puck Adapter OEM B67875878.
bluetooth puck.jpg
bluetooth puck.jpg (32.9 KiB) Viewed 3468 times
Phone network: Three
Country of use: England, UK.

So I started out with using the rSAP trial version and quickly realised that I needed to also use the rSAP installation app first prior to installing the main rSAP app.

The installation app needs root to work so I needed to root my phone. Eventually I found a nifty piece of software called 'Nexus Root Toolkit' that can be found here: This software enables you not only to easily root your phone but also flash a new ROM, unlock the bootloader, and also restore your phone to factory settings if required. I must point out that rooting and flashing ROM's is not risk free and could result in you bricking (making unusable) your phone. Modifying your phone will also wipe it, so make sure you have anything you want to keep backed up.

I also recommend using either of the following apps to backup your phone before messing with root and new ROM's:
TWRP (Team WIn Recovery Project) or Clockwork MOD ROM manager.

So once I gained root I installed both the rSAP installation app and then the rSAP app, and then I needed to connect my phone via bluetooth to my car. That was a tricky job, I used this for inspiration: ... LR_Web.pdf. But ultimately just ended up using trial and error! Here is a summary of how to connect:

Firstly you must understand that the headunit its self has bluetooth which the phone will pick up when you search for nearby bluetooth devices, this is a RED HERRING! Your phone does not actually connect directly to the headunit but uses the above bluetooth puck for its connection to the Comand system. The only way I found to successfully connect to the car was getting the Comand system to find my phone, not the other way round. Ie. You cannot get your phone to find and then connect to the car.

So here's my step by step guide:
1) Enable bluetooth on your phone, and make sure the rSAP app is working correctly.
2) Make sure your phone is visable to bluetooth devices.
3) Power up your Comand system in the car.
4) Find the bluetooth puck (usually found under the armrest in the centre).
5) The Mercedes symbol on the puck is a button (I didn't know that at first!). A press and hold of around 3 seconds will make the blue LED's flash either side of the button and the puck will begin searching for bluetooth handsets. A press and hold of 5 seconds or longer will erase all the bluetooth devices from the puck's memory and make the blue LED's flash faster.
6) So press the puck button for 3 seconds
7) Press the 'Tel' button on your headunit, and you should see 'please wait' displayed.
8) Use your steering wheel buttons to display 'tel' in your instrument cluster.
9) After awhile 'BLUETOOTH' should appear in your instrument cluster. This means the puck has finished searching and has found a device(s).
10) On your steering wheel there are 4 buttons on the left and four on the right. On the left the outer most buttons are used for navigating thorough the Comand menu system, and the inner most left hand buttons are for navigating through the sub menus.
11) Using the sub menu navigation buttons scroll down and you should see your device come up on the instrument cluster. I had 'Nexus 4' displayed, but it will display whatever you've called your phone.
12) Once your phone is on the cluster display press the steering wheel button 'answer call' (the one on the right, that has a symbol of a phone lifted)
13) On your headunit display you should see a long code (14 digits I think), also displayed on your instrument cluster (but you can't see all the digits on there). The code is a series of numbers in pairs eg; 11223344556677.
14) After a short while your phone will get a pop up message asking to pair with MB and asking for a code. Enter the code that is displayed on your headunit, and hit OK.
15) If pairing is successful you will hear a set of 3 ascending beeps emit from your car speakers.

I performed all the above, and the phone was connecting to the car correctly, but now I couldn't make or receive calls, aarrggghh!! All I had on the instrument cluster display was 'provider search' when I had the 'tel' menu displayed. Google held the answer, yet again. The problem was my network, Three. They don't allow your SIM to be 'taken over' and so have something that prevents you from actually making calls etc. I had to change networks, and now I'm using GiffGaff (who use the O2 network) and everything is great!

A few disadvantages of rSAP:

It can't access your contacts stored on your phone memory, it can only read contacts that are stored on the SIM.

Once your phone is connected to the car system you lose all mobile signal on your phone, because the SIM is 'taken over' by the car system. This means your phone cannot send/receive data, so you lose internet connectivity.

If you connect to the Comand system with your phone and are in an active call when you switch the Comand system off you lose the call.

SMS text messages received while connected to the Comand system are not 'seen' by your phone but are 'seen' by your headunit. You'll notice a envelope symbol appear near the bottom right of the screen on the headunit when you have an unread SMS text message. This can be read by pressing the 'serv' button on the headunit and then going into 'mailbox' or something like that. But whatever messages are sent and received when connected to the Comand system will not be displayed on your phones messaging app.

You cannot play music through the car system when connected. I use a 3.5mm Jack to Jack cable and plug my phones headphone socket into the car socket (found in the left side of the glovebox) to play music from my phone in the car.

So if you can't live with the disadvantages, what are the alternatives:

This Viseeo MB-4 has good reviews. It replaces the bluetooth puck in the armrest, and then intergrates into the Comand system. Not cheap at £200, but it will supposedly display all your phone contacts without moving them to the SIM, and I imagine you would still have an active internet connection on your phone when connected via bluetooth to the Viseeo. However, it still won't let you stream music over your car stereo system. If you wanted to stream music then you'd need the Viseeo MB-3, which is around £220. This has a built in FM transmitter, which will play music from your phone via bluetooth but then emits an FM signal (of your choice) that you tune your headunit in to. I believe that the Viseeo system also enables you to use your steering wheel buttons to control phonecalls etc.

Fiscon offer another alternative called the Fiscon Pro Bluetooth Phone Kit for Mercedes Benz (MOST based cars). It costs around £350, and would probably need a professional to fit, unless you are confident with car electronics. I believe this system is an ideal solution; streams music, reads your contacts, utilises the steering wheel buttons, lets your phone have internet access. It only has two disadvantages as far as I can tell, firstly it cannot use the built in Mercedes microphone so you have to put up with having an additional microphone fitted, and secondly it uses the CD changer connection on your headunit so it makes your CD changer redundant and useless.

So when you compare the above alternatives to paying £7.50 for the rSAP app I think it's a no brainer! But I've tried to be as informative as I can so you can make your mind up.

Please reply if you think I can help and you have a similar system to mine, if I can assist I will.


Adam :)

Posts: 9
Joined: Fri Nov 29, 2013 11:57 pm

Re: rSAP working with Nexus 4 (at last!) and some alternativ

Post by Gagome » Fri Feb 20, 2015 1:20 pm

It can't access your contacts stored on your phone memory, it can only read contacts that are stored on the SIM.
You have an old rSAP bluetooth adapter in your car. I guess yours is even the original V1.
And that is the reason why you only have access to the contacts on the SIM.
This is not a restriction of rSAP but a restriction of the old puck Bluetooth adapter you are using.

I have used newer Mercedes rSAP Bluetooth (V2, V3 and V4) adapters and they all could access the contacts from phone memory.
Currently I am using the latest Mercedes V4 Bluetooth adapter and it works great.

Another big advantage of rSAP you forget to mention is the fact that with rSAP you are using the external antenna of the car. You have usually better network reception with the car phone because of that.

Posts: 2
Joined: Thu Feb 19, 2015 7:32 pm

Re: rSAP working with Nexus 4 (at last!) and some alternativ

Post by adammitch » Mon Feb 23, 2015 6:57 am

Fair points gagome. Of course I'm only relating to my own experience of using rSAP, with my own particular set up.

So do you think it's worth me upgrading my bluetooth puck? Will the only extra advantage be that it can read contacts stored on my phone?

Posts: 9
Joined: Fri Nov 29, 2013 11:57 pm

Re: rSAP working with Nexus 4 (at last!) and some alternativ

Post by Gagome » Mon Feb 23, 2015 11:54 am

When you upgrade to a V4 SAP module you will certainly get the functionality to access the contacts from phone memory.

Additionally it may be possible that your Three network may work. The V4 SAP module allows 3G UMTS connections. And as far as I know the problem with Three is that they only use 3G and don't support GSM (except roaming) and that is the reason why your puck SAP module didn't work with the Three SIM card.
But I can not verify if this is really true and if the V4 module using 3G will work with a Three SIM card.

V2 and V3 SAP modules don't support 3G.
With such a module your benefit would be to have access to the contacts from phone memory.

The newer modules have several bug fixes too. At least that is what I could read in the documentation.
And the newer modules allow more phones to be paired. Not active at the same time, of course.
But when you have more than one phone you could pair all of them and the SAP module tries to use the last used phone, if it doesn't find it it searches for the next. It does this automatically and you don't have to pair any phone again.
If you only have one phone this function would be of no use to you.

The V4 module has firmware update functionality. And there is a firmware update dated 04 2014 available for a V4 module which fixed some problems. After I have updated the firmware of my V4 module to this level it worked better.

So, if it is possible you should try a V4 module.
But I know that these modules are not cheap.

Site Admin
Posts: 4139
Joined: Wed Mar 23, 2011 4:12 pm

Re: rSAP working with Nexus 4 (at last!) and some alternativ

Post by admin » Tue Feb 24, 2015 12:40 pm

I'd also recommend the V4, since there have been more reports of problems with the V3. In German eBay it's no problem to get a V4 for 150€-200€, the V3 is only about 50€ less.

Post Reply

Return to “Mercedes-Benz Bluetooth (SAP) telephone module”