A telephone switchboard is a computer program that links calls. When we use our mobile phone to call another individual, our call passes through several switchboard exchanges until making the recipient's telephone ring.
During this procedure the user calls the switchboard, it processes the user's needs, it looks for an interpreter to meet those needs it calls the interpreter and transfers the user's call and the interpreter into a virtual room in which they carry out their conversation. If required, it can additionally call a third phone number and add it to the virtual room as well. When the call finishes, the switchboard records all the data relating with the service and hangs up all the calls.
Cabrera, Gabriel. Technological Progress Allowing for Telephone Interpreting in Spain. 2017