Dual Tone Multifrequency (DTMF) transmits control information over a voice channel. Each digit uses two different frequency burst modes for sinusoidal coding. The dual tone mode is chosen because it can reliably distinguish dialing information from voice.
Compared with short message and GPRS control mode, DTMF technology has the advantages of simple control and high real-time performance. It is welcomed by security alarm, intelligent control and other application customers.
At present, most manufacturers adopt the external DTMF encoding and decoding chip to detect DTMF. The remote communication embedded the complete DTMF and the specific frequency monotone encoding and decoding function in the GSM/GPRS module, and provided a rich DTMF transmission interface scheme. The newly developed DTMF function for internal decoding of remote communication module has high decoding recognition rate in applications where the amount of communication data is not large and the communication rate is not high.
Intelligent detection of DTMF voice without any external circuit and active reporting from serial port
Save space and make it easier for customers to design products
Convenient AT instruction to adjust the loss and weight rate of audio decoding