The 3G communication modules described below can realize: receiving and sending a 3G signal, converting the 3G signal into data of voice service or data service, and then sending it to an Application Processor (AP) through a certain interface.
At present, the application of the 3G communication module still belongs to a developing technical field, and there is no standard for the interfaces between 3G communication modules and the APs. Most 3G communication modules keep using the connection mode between a data card and a computer, and use a USB interface for connection. In the operating system of the AP, a port for the virtual voice service and the data service is used for realizing interaction between voice and data. Such connection mode has a problem that the USB interface is not adapted to be applied in equipments with low power consumption, such as a mobile terminal, due to its high power consumption. In order to solve the problem of high power consumption of the USB interface, some 3G communication modules use a Pulse Code Modulation (PCM) interface to transmit voice service data and a Universal Asynchronous Receiver/Transmitter (UART) interface to transmit data with a small volume. Only in a case of a relatively large data volume, a high-speed USB interface is used. One to four General Purpose Input Output (GPIO) interfaces is used for the wakeup between the 3G communication module and the AP.
As the development of the Internet of things depends on the fixed network and the mobile network, the efforts of telecom operators in China in the research and development of the Internet of things will further accelerate the development of the Chinese industry of the Internet of things. With the rapid development of the Internet of things, 3G communication modules will be widely applied in various radio communication fields. Therefore, the APs connected with 3G communication modules will also be more diversified. An AP in a traditional smart phone or netbook has many interfaces, such as USB, PCM, Inter-Integrated Circuit (I2C) and UART. While in industrial or simple civilian radio communication fields, some APs are applied in an application environment relying mainly on programmable logic controller (PLC) or simple single chip machine. These APs do not have abundant interfaces to connect with 3G communication modules, therefore connection between 3G communication modules and APs is limited.