Tinkering with Raspberry (and other things)

Quick Tip: Which Bluetooth Services Does My Mobile Phone Offer

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Ok, this has nothing to do with either the Raspberry Pi or any Android device but I think it may be helpful. At least it is for me.


I own a car with a rather expensive and somewhat “feature rich” hands-free equipment. It is capable of using the normal hands-free profile (HFP) or, and that is my preferred connection method, something called “rSAP” (remote SIM Access Profile). This means that the phone transfers the SIM credentials to the car’s system and this is then acting as a mobile phone with my SIM-card inserted (when, in fact, my SIM card stays in the mobile phone). The advantage of using this profile/technology is that the car uses its own outside antenna thus having less electromagnetic signals inside the car and a much better reception of signals.
As I came to understand the rSAP technology is not much used outside Germany/Europe. In fact, from discussions with friends from the US I came to the conclusion that rSAP is fairly unknown there.

The Problem:

rSAP is not a standard component of Android. There is an app in the Play Store that works (more or less) but it needs a rooted phone (no problem here, that is the first thing I usually do on my mobiles). Some Samsung mobiles (S2 and S3) with some (not all) Samsung stock firmwares do support rSAP.
And here’s the catch: if you update the Android system on the phone there is no guarantee whatsoever that the new version will have rSAP support built in. And most annoyingly, contacting the Samsung support does not help because the people there have no idea what “rSAP” is.
So what you could do is update the phone, walk to your car and check if rSAP works. Which, in may case is not very efficient because my car is parked in an underground car park 5 minutes from where I live. So I need to walk to my car, drive it out of the car park, check if everything works and then drive the car to my underground car park again…

The Solution:

Bluetooth services are announced or better, can be queried by applications. So it is much more convenient to flash a new Android version, query the Bluetooth services available from my computer and then continue or (after some swearing) revert to the previous Android version that had the rSAP service built in.
On my Mac there is an app called “RDP Browser“. It is freeware and works like a charm, even with Mavericks.

So my “workflow” now looks like this:

  1. Make a backup of my mobile phone
  2. Flash the new firmware
  3. Connect the mobile via bluetooth to the Mac
  4. Run RDP browser and look for a service called “SIM Access Server” and “OBEX Phonebook Access Server”
  5. Smile if it is there, swear if it is not and in that case: reflash the old firmware


Here’s a screenshot of the services offered by my Galaxy S3:

Bildschirmfoto 2014-05-23 um 18.39.38

Things were much easier with my Nokia E51. There were no updates and rSAP just worked. Well, in fact I did not yet update to Android 4.3. First of all because I do not want the Knox bootloader, second because I am getting more and more annoyed with Android (and iOS, by the way). It was fun and cool in the beginning but nowadays both operating systems get more and more into “gated communities” and I do not like that. Period. What happened to “Do no evil”, Google?

And, before the question arises: I own a Volkswagen Golf GTI Mark VI with the “Premium Freisprecheinrichtung” (PFSE). Why? Midlife crisis and not enough money for a Porsche, I suppose. No, seriouslyy: I wanted an everyday practical car that, when I’m driving it alone, would put an evil smile on my face every time I kick down the acceleration pedal…


One thought on “Quick Tip: Which Bluetooth Services Does My Mobile Phone Offer

  1. Awesome, I am glad youposted this. I was just thinking how anoying it is to see just a number on my Subaru Outback sport 2011 (they decided to wimpyfy them starting 2012) radio display. BTW it is an horible handsfree system, Subaru!
    Anyway I use the NOKIA N900 with Debian running as OS and I was thinking if there is anything smarter outhere this system. I always have to guess who owns that number when it shows up on the radios system.
    But where I am going with this…. I have an old Ford pickup truck where I want to build my own hands free system using RasPI. Thus, I am thankful to learn about the rSAP. Once I get it working with my N900 which is probably going to be a challenge by it own I will post an update with the link. Thank you for the rSAP info. Keep posting these things.