Living far from one’s home country, working remotely, frequent travel, or maintaining a presence in another country often necessitates a reliable telecommunication system to stay connected globally.
Target users
- Remote workers
- Travelers and tourists
- Digital nomads
- Expats, migrants, and students
- International businesses or businesses with multiple branches
- Transport and logistics companies
- Travel agencies
- …and more!
These users often seek:
- A local SIM card for local calls and internet browsing.
- A way to receive calls on their original (home) phone number without incurring high roaming fees.
- A cost-effective roaming solution.
- A virtual presence with a local phone number in a remote location.
- Low-cost calling options.
Solution
This can be achieved by setting up a phone system with the following components for low-cost or zero-cost calls between locations:
- VoIP server: This could be a hosted PBX or a small server (e.g., an old computer, Raspberry Pi, OpenWRT router, or VPS) running Linux and Asterisk PBX.
- Prepaid SIM card: For use in the current location.
- DID phone number: A Direct Inward Dialing (DID) number in the home (or remote, for virtual presence) location. This number, obtained from a VoIP carrier, can be forwarded to your phone system. Alternatively, an FXO/VoIP box can connect your home phone line, or a Raspberry Pi with a GSM USB stick/gateway can utilize your old SIM card.
Set up call diversion from your home SIM card to the DID number (or keep your SIM card active within the GSM gateway).
Configure a SIP account on your softphone and point it to the VoIP server.
Update the dialplan to start receiving calls effortlessly.
This system supports calls in both directions. If internet coverage is unavailable, calls can be routed to a mobile phone via a VoIP trunk. While this may involve a fee, it is generally more economical than standard roaming charges.
I have personally used this method for years and am currently developing a roaming PBX solution to automate various use cases.