reason: volte function is not turned on. After volte function is turned on, you can surf the Internet while making a phone call. You can contact the operator's customer service for advice on how to open volte. volte has many advantages, such as improving the call quality and reducing the call connection delay.
Telephone [English: telephone, from Greek? λε(tēle, meaning "far") and φ ω ν? (PH ? n ē, which means "sound"), the old translation is a long-distance communication device that can transmit and receive sound. As early as the 18th century, there was a word "telephone" in Europe, which was used to refer to a microphone strung with wires (a cup strung with wires).
The appearance of the telephone is attributed to alexander graham bell. The principle of the early telephone is that the voice is a compound vibration in the air, which can be transmitted to a solid and transmitted to a conductive metal through an electric pulse. Bell applied for the patent right of the telephone in March 1876.
On June 15th, 22, the United States Congress confirmed Antonio Muzzi as the inventor of the telephone. Muzi first showed his invention to the public in 186, and published an introduction about this invention in an Italian newspaper in new york.
The improvements and inventions of telephone in history include: toner microphone, manual switchboard, dial, automatic telephone exchange, program-controlled telephone exchange, dual-tone multi-frequency dialing, voice digital sampling and so on. The new technologies in recent years include ISDN, DSL, VoIP, analog mobile phone and digital mobile phone.
this industry is usually divided into telephone equipment manufacturers and telephone network operators. Historically, network operators usually have a national monopoly. In recent years, with the opening and integration of the global telecommunications market and the development of technology, there has gradually emerged a situation in which many operators compete in the same market. For example, the Bell system.
at&; T's subsidiary once owned 8% of the American telephone market. In 1984, due to the anti-monopoly lawsuit of the US Department of Justice, Bell System was forced to be partitioned into several independent local Bell companies. There is a saying that can explain this phenomenon: At&; Before t was partitioned, IBM was the second largest company in the United States. At at&; After T was divided into seven companies, IBM ranked eighth.