Guide 01 · one connection
How a call travels
From microphone and signalling to radio access, routing, the receiving device and call release.
Follow the path →Mechanisms without mythology
Look through the object.
A handset is only the visible terminal. These guides follow signalling, switching and identity into the network while keeping important distinctions intact.
Guide 02 · four identities
Handset, SIM, number, account
Why these related things are not interchangeable—and what actually moves when a SIM changes phones.
Separate the layers →