Bluetooth/USB/WiFi/CarPlay/SIM relationship

[TimothyN]

Is anyone able to explain what is the connection (npi) between Bluetooth, the wired connection, CarPlay, WiFi and the two SIMs?

I think we all know that it's pretty flaky all the time. I very often have to reconnect CarPlay manually and I am used to not agreeing for the connection to transfer from BT to wired, as that can cause disconnection.

And on a regular basis CarPlay stops working altogether and you have to get both parties to forget the other on BT, and pair from scratch to get CP to work. But if you have a wired connection, why does CP even need BT to work?

Then on top of this there is the whole WiFi thing. What is its role?

And the car has an eSIM while the iPhone also has a SIM. Which SIM is used for what when CarPlay is in use?

Can anyone, maybe with a graphic, explain how all these different connectivities between car, iPhone and the phone network interact?

 

[stevedee]

The car SIM allows internet access for the car, & for MG & you to communicate with the car remotely; you using iSmart via a French server. It also enables other net stuff like YouTube, & can operate as a hotspot for your phone.

We have not had any Bluetooth problems using our OnePlus phones; a 5 and an 8

The USB socket furthest from the driver includes a wired connection to the car & can use Android Auto. This is data heavy, so best wired (not wireless like BT).
However, if you don't want AA connection, you just want your phone powered/charging/using BT ( maybe for music), then use the USB socket nearest the driver. The system won't then connect/nag you to connect to AA.
We have coloured cables connected to these 2 USB sockets, so we know which is which.

I've had a stab at producing block diagrams, but sure to be configurations I've missed.

Probably best viewed on a laptop or a screen larger than the typical phone. See attached PDF...

 

[TimothyN]

That's really kind, thank you.

I will look later. I've no doubt I will be full of questions, but that will help me frame those questions...

 

[TimothyN]

Thank you. It does leave me full of questions, as expected.

The main one remains that CarPlay seems to be dependent on BT, even when connected via USB cable.

 

[stevedee]

I don't think that's true, but remember that only one of the 2 USB C sockets that they have hidden away in the central box supports it; the one with the boxy window icon.
Try disabling BT on your phone, just as a test, then see what happens.

 

[TimothyN]

OK, right, thank you, I now accept that CP works on USB without BT.

But then, of course, BT functions, such as phone calls, are no longer available.

When you switch BT back on and reconnect, it switches CP off, and you have to reconnect, so there clearly is a binding or relationship.

I wish I understood it in detail, so I could discover how to quickly restore CP when it stops (and I am inevitably trying to navigate in places I have never been before in the dark, as I was last evening in some Putney backstreets.)

 

[stevedee]

...when you switch BT back on and reconnect, it switches CP off, and you have to reconnect, so there clearly is a binding or relationship...

I'm hoping that others will step in & say how their cars behave, as we have not seen this. When we plug in the OnePlus 8 to the correct socket, CP connects (if enabled in the CP menu) and other functions like making/receiving phone calls function as expected.

 

[deviousrich]

just to add...

car play / android auto have multiple connections between the phone and the car (and get confusing)....
typically Bluetooth is used to start the connection between the phone and the car (whats called a device handshake/discovery) and then a (local) wifi between the car/phone is setup (behind the scenes so to speak) which does the actual displays, apps etc on the car head unit.

But.... calls for example (if you route them through the car head unit) still use bluetooth as its the most mature / stable way to route calls across devices (HFP is Hands Free Protocol which is how bluetooth calls work and has been around way before android auto).

When you use wired android auto you are basically skipping the discovery/wifi but some audio will still need to route over bluetooth (ie calls)

 

[TimothyN]

It sounds as if it's really not predictable which technology is going to be used for what. What I do know is that every couple of weeks everything collapses, and I have to delete Bluetooth from both ends and restart the whole process to get anything.

 

[morleym2002]

It sounds as if it's really not predictable which technology is going to be used for what. What I do know is that every couple of weeks everything collapses, and I have to delete Bluetooth from both ends and restart the whole process to get anything.

Carplay seems to be the common problem with mgs5 connectivity. My Android phone works wirelessly every time I enter my mgs5 I have never had any issues with connectivity

 

[TimothyN]

Much as I resent giving a cent to him, I have just invested in Starlink. It's going to be interesting to see how that changes the dynamic.

 

[Mark B]

Carplay seems to be the common problem with mgs5 connectivity. My Android phone works wirelessly every time I enter my mgs5 I have never had any issues with connectivity

Same for me with my iPhone and CP. It just works.

 

[TimothyN]

There are so, so many variables that it would be really difficult to work out why some installations "just work" and other others are a world of pain.

 

[TimothyN]

To continue this theme, I now have my Starlink Mini and thought I'd try it in the car. It works brilliantly and, in this part of the world (which includes, ridiculously, the M25 between J8 and J5, where the GSM signal is atrocious) is far better than relying on mobile networks.

But, annoyingly, connecting the iPhone to the Starlink Wi-Fi means that I lose CarPlay. I don't understand why, as the CarPlay is connected via the USB wire.

Any workarounds to allow me to have Starlink and CarPlay at the same time?

 

[stevedee]

One unexpected joy of my S5, is that I like to stream Radio Caroline from an app called Transistor on my phone over Bluetooth.

The unexpected bit is that I can get back into the car days later, & the car system just starts the app & plays Caroline.

No idea how it does that. I'm not using Android Auto.

Hell, my phone is not even running a 'proper' Android operating system!