Mobile phone Asterisk interoperability

[ghlaier]

Suggestions for implementation patterns and tools are welcomed… I have double-posted this on both the Asterisk community server and my blog www.denfriedanske.dk/blog.html
Please do not suggest an online service. I am looking for a bullet-proof DIY solution of high quality and at a low cost.

I want to set up a physical connection between an Asterisk server to my mobile phone provider represented by a SIM card and a (national) mobile phone number (LTE or 5G) with SMS/MMS and other services. The physical gadget holding the SIM might be an Arduino with a GSM module, a raspberry pi with a broadband modem, or a mobile phone connected through a USB port. To be placed on my desktop or elsewhere 24/7. The sim card itself should be able to provide both internet, and phone calls, and SMS/MMS messaging. MMS messages capability is more a question of parsing SMS messages than coming up with a completely new read/write capability for the solution.

Aim: To be able to receive and send SMS/MMS and pass mobile phone calls seamlessly on a softphone app iOS/Android on a worn smartphone disconnected from all but a single band, i.e. 1800MHz, or connected to the internet using wifi/Bluetooth or USB tethering.

Staying disconnected I get a super safe system with the potential to add security measures like PiHole and using proxy servers for added security, getting rid of js trojans from both authorities and private crackers. It is also a system that makes it harder to locate the caller.

Daily use:
I can store SMS/MMS messages on the server at home, while I await a hot spot opportunity. Going offline several times throughout the day is not that important, I do not work as a receptionist. The Asterisk server will provide the voicemail capabilities of professional companies for me as a private user, and I see commercial potential in the solution or at least a market-changing potential migrating telephone traffic to the internet increasing degree of security through encryption techniques and advanced cisco. Puts a competitive strain on the telephone providers, eavesdroppers, and damaging unconstitutional authorities.
On another softphone app (same or different worn smartphone) I can add a business-related link to a more traditional appliance of the Asterisk server and all the capabilities needed for professional service; an application of Asterisk described elsewhere.

[InterLinked]

You talk about “bullet proof” and “secure”, but then you repeatedly bring up SMS/MMS, both of which are laughably insecure. If you are concerned about eavesdropping and encryption, I think you need to re-evaluate your plans and SMS should not even be in the same paragraph as those other words.

As such, I don’t really follow what you’re trying to accomplish, and I’m also not sure what’s “market changing” about what you mention, VoIP is easily doable today and people and companies have already been taking advantage of it.

[ghlaier]

@InterLinked. If the services are locating my phone on the desk at home using a single band, i.e. 1800 MHz, communicating through LTE, this is not a breach to my security on an ordinary scale. At least I have removed GSM, 2G and 3G.
The line I want to secure with extraordinary measures is the one between my desktop and my smartphone running a softphone with texting capabilities. As an ordinary telecommunications user, I need to receive and send messages. I should be able to construct a solution that will use different channels within my own infrastructure for conversations and messaging.
Your concern asks for a feature: To use SecureSMS when possible for an encrypted channel for messaging through my SIM card on my desktop.
Thanks. Any links to similar chats, tutorials, DIY setups, videos will be appreciated.