I have an older BMW with a BURY/THB UNI System 8 hands-free installation. The system originally used a Nokia phone cradle, and I would like to adapt it so that I can use a modern phone, such as an iPhone, over Bluetooth.

I am trying to decide between two possible approaches:

1. Designing an adapter that connects a bluetooth module directly to the BURY System 8 / Universal adapter interface.
2. Reusing the existing Nokia cradle and its Nokia Pop-Port connector, and building a Pop-Port-to-Bluetooth adapter.

I don't yet know which approach is electrically simpler or better. As a matter of fact i am actually on a pretty beginner level in electronics and i actually wanted to take this project on to improve my skills. I would like to understand the pinouts and signals available at both interfaces before choosing one.

The car currently has a BURY System 8 installation. The setup consists of the BMW wiring, a BURY System 8 control unit/base, the System 8 BasePlate, and a removable Nokia cradle.

The Nokia cradle is labelled as compatible with:

* Nokia 3100
* Nokia 3200
* Nokia 6100
* Nokia 6200
* Nokia 6220
* Nokia 6610
* Nokia 6820
* Nokia 7210
* Nokia 7250
* Nokia 7250i

The cradle uses the standard Nokia 14-pin Pop-Port connector for the phone.

BURY made the System 8 as a modular system, so different phone cradles/accessories could be attached to the same BasePlate. BURY also produced Bluetooth versions of the System 8 accessories.

I also found this Official BURY System 8 documentation, don't know if it's useful: [https://www.bury.com/en/products/s8/](https://www.bury.com/en/products/s8/)

My goal is to keep as much of the original BMW/ BURY installation as possible and make it usable with a modern phone.

Ideally, I would like:

* Bluetooth connection between the phone and the adapter
* Bluetooth for phone calls
* use of the BMW/ BURY microphone
* call audio through the BMW speakers
* potentially retention of the original call buttons/controls, depending on how the system works
* possibly power the adapter from the existing BURY system
* Music capabilities

My current instinct is that reverse-engineering the Nokia side may be easier than reverse-engineering the proprietary BURY System 8 connector, but I may be completely wrong about this.

How should I proceed to add Bluetooth to an old BURY System 8 BMW hands-free system using the existing Nokia cradle?