It is the function of line in, which is support by allwinner A20 chip , but this function is rarely used by people, and our board is not drawn out. if you want this , you need to customization boards.
Thank you for the answer, but honestly I’m very disappointed with him.
Please do not take my response as a desire to offend anyone.
However, it actually turned out that RPI solutions are the most famous microcomputers in the world.
The people who purchase them want to solve a variety of problems with their help, including telecommunications, including VoIP. And the ability of processors quite allow this.
It’s very strange that I can watch streaming broadcasts without difficulty, including in high resolution, but I can’t use the SIP client. Meanwhile, the chipset, as you rightly noted, provides such a technical opportunity.
Really, on what planet do developers live? They brought to the connectors a lot of different signals, but about to brought into a single pin audio input is not thought!
You mentioned customization of the board. And what can be done for this?
In ARM world you buy hardware for your purpose. If you go the other way around, its simply wrong way.
Famous yes, but also very stupid in term of bizarre construction and very closed - Linux runs inside closed source RTOS … Also general purpose, where compromise is the first thing you will need to do.