If you travel a lot, are you used to unreasonable mobile roaming charges? However, mobile phones are sometimes absolutely necessary-we have to pay for mobile roaming while working overseas or on vacation, because we need to keep in touch with the office and talk to people around the world about the Raspberry Pi.
Holger Leusch, Benjamin Reichel and Karina Hochstein all faced such problems. To make matters worse, Holger often goes to Cambodia, but his German mobile phone provider has not even signed any roaming agreements with Cambodian telecom operators, so he simply cannot continue to use the original mobile phone (number). Cambodia's reluctant call quality, disgusting bandwidth, delays, and disconnections made him unbearable. The reality is that, like us, he needs to keep in touch with the office.
Enter the realm of Raspberry Pi:
Many people are located in places, and might consider buying a gateway based on SIP-GSM. However, GSM gateways are not cheap: Holger research found that a single GSM-side gateway (you definitely need two, one in each of two locations), the price ranges from 200 to 400 euros. If you invest such a high price, how many phone calls can you make? So, the three of them did it themselves, and the final choices included: running RasPBX via Raspberry Pi, Huawei 3G wireless network card, Asterisk ’s Huawei 3G wireless network card driver, and USB mode conversion tool. The full set is worth about 75 Euros.
Holger says:
Now, when someone calls my GSM number in Germany in Europe, first my domestic mobile phone will ring, and after 5 seconds, it will be transferred to my Cambodian mobile phone. As a by-product, from now on, my Cambodian friend can call my Cambodian mobile phone, and eventually make a call or send a text message with my German mobile phone, the call fee is very cheap ...
Spanning more than 10,000 kilometers, the connection quality brought by the 64 kbps Asterisk “SIP trunk†trunking technology between the two gateways is really awesome. The people who talked to me did n’t even notice that I was overseas. It should be noted that Ofcom, the British communications management agency, said that in some countries, the telecommunications laws related to GSM gateways are still vague:
Ofcom recently clarified that according to British law, as long as it is for its own use, it is completely legal for users (whether businesses or ordinary consumers) to purchase, install and use GSM gateways. However, no one is allowed to use GSM gateway equipment to provide communication services to other individuals, organizations, or commercial institutions. Otherwise, regardless of the geographic location of the gateway equipment or the number of end users connected to each gateway, it will be illegal. This "commercial" use ban also applies to mobile network operators (MNOs) and other organizations because the current licenses of mobile operators have not been extended to the installation and use of GSM gateways.
Basically, you can build your own gateway in the UK-but if you try to sell or rent this service, you will be miserable. However, if you want to use this method to save roaming charges, the mobile network operator sometimes takes further action. For example, if the mobile operator suspects that you are using a SIM card for the GSM gateway, the operator may deactivate the card. Therefore, before taking this action, you must carefully study the local regulations.
ofGEEK:
RasPBX is a complete installation tool for Asterisk and FreePBX running on the Raspberry Pi.
PBX (Private Branch Exchange) user-level switch
Asterisk is an open source software VoIP PBX system. It is a pure software implementation solution running in a Linux environment. It is a very full-featured application that provides many telecommunications functions and can turn your x86 machine into a Your own switch can also be used as an enterprise-class commercial switch.
FreePBX is one of the most powerful GUI (web-based) tools for configuring Asterisk. It provides everything a standard traditional telephone system can do, adding a lot of new features. FreePBX was previously called Asterisk Management Portal, which is a standardized implementation of IP phone tool Asterisk, which can provide a web configuration interface and other tools.
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