Have a duo-SIM phone since many years, but did not use the second SIM actively, until recently. And guess what: it seems the MB COMAND 5*5 bluetooth/phone module does not support making calls from the COMAND Phone Menu. Incoming calls works great, outgoing works when you make the call from your phone itself, but when trying to redail a number directly from the COMAND Phone menu (e.g. from missed calls or from the phonebook), it will end (after a few seconds). Even when you set 1 SIM as the default Phone SIM on your phone, it does not work. If you comnpletely disable the second SIM on your phone, it works as usual.

When connected via Android Auto, you can use the AA Phone interface to make the call (there it works when 1 SIM is default, but also when you have to choose SIM 1 or 2 just before calling). This is a (clumsy) workaround, but does anybody here know how to make calling numbers work again with 2 active SIMS active (of which 1 is default for calling out) using the MB COMAND Phone menu?

 

I'm pretty sure this is your phone that is having the issue. As far as I know, Bluetooth calling doesn't have specific support for dual SIMs. It's up to the phone. I used dual SIMs during my European Delivery trip with my iPhone XS, and I don't recall having any issues. On the iPhone, one configures the desired SIM for each contact, and then it uses that SIM regardless of how the call was placed. The default SIM is only used for the initial configuration of all contacts and when dialing a plain number. Doing some quick Google searches, this seems to be somewhat of a known issue with Android. One particular issue seems to be if the phone is configured to ask for the SIM, then when you place the call over Bluetooth, the phone pops up the SIM selection screen and you have to select the SIM to use on the phone before the call goes through, and probably if you don't do it in time, it cancels the request.

 

Thx for the confirmation that at least with an dual sim iPhone this works normally. My phone indeed is an Android (11), and I set 1 SIM card as default, so on the phone NO popup asking for which SIM to use seems necessary. Also on Android Auto it works (without choosing any SIM, since the phone chooses the default SIM). Will dive deeper into it from the Android side of things, but happy to hear experiences from other MB COMAND 5*5 users about this!

 

Did indeed found a lot of issues online with dual SIM phones connected to a built-in carkit/car entertainment system.
Was about to install this app on my phone: https://play.google.com/store/apps/d...ltisimselector that seems to solve the issue for some people.

But just before, I got an Android 11 firmware update for my phone, installed it, and after this...........it worked as it should be! So using COMAND Phone it chooses the default SIM as set in the phone (without using the afore mentioned app).

So problem solved!