The design and testing as it now stands:

        The design:

           The mobile phone device is a modular system. The Phone client device will be a stand alone device housing the cellular board, Raspberry PI Zero W, battery, small display, and nav buttons. With this device alone one can send/receive phone calls and SMS. Hopefully it will be pocketable.

           The display device, aka the Phone broker, also a stand alone device, will house the touch display, Raspberry PI CM4, battery, camera, and some buttons. Without the phone client, this device will connect to any wifi and be a basic tablet, but when connected to the client, they will communicate using mqtt sharing cellular status, control the cell device and other management type actions that can be displayed on the display device in the python gui phone app adapted from the OURS-project.

           Being a modular system, new devices can be easily added to the system, such as a large display module, other cellular modules, packet radio module, Lora wan module and other things that i haven't thought of yet. Some modules would require different software and/ or user interfaces.

        The hardware connections:
            The 4G cellular module is connected via USB to the Phone client, a Raspberry PI Zero W. This pi will control the phone module and provide wifi connectivity to the Phone broker.
            The Phone broker is the Raspberry PI CM4 and it hosts a wifi hotspot that the Phone client connects to.

        Testing so far:

              The Phone broker hotspot  is working

              The Phone Client can connect to the broker.

               Mqtt messages can be transferred between the two.

    The next steps:

       Establish internet connectivity to the Phone broker via the Phone client

       develop python code to control   cell module via mqtt and provide status to the broker

       Adapt the phone.py gui app to utilize mqtt