Based on the GSM network of fire alarm network monitor design (1)

Preface

Fire alarm network monitor is a fire alarm system and urban fire alarm network monitoring center of an intermediate device, it completed the fire alarm system and urban fire alarm network monitoring centre information forwarded.

City fire alarm network monitoring center only by fire alarm network monitor before the entire city of fire alarm system into a fire alarm monitoring network, to quickly master the dynamics of urban fire. City fire alarm network composition as shown in Figure 1.

　　

Traditional city fire alarm Network General is based on the PTSN network (PSTN) to communicate through DTMF signals.

Fire alarm network monitor use modem chip to send and receive DTMF signal, network monitoring centers use voice cards device to send and receive DTMF signals, use PTSN network of city fire alarm network enabling low cost, high reliability of communication, it has been widely used. But in actual use also found some shortcomings, network monitor use of the telephone line if the user phone line with line effect appears when the user's normal call, in order to communicate reliable need separate, dedicated phone opened, this adds another cloth line, the additional workload. And wired connection to the telephone line is also more vulnerable to the influence of external factors such as the lines of communications failure affects systems running reliably. If you can use Wireless GSM network to achieve network monitor and monitoring center of communication should be a good choice. But for early communication of GSM network reliability, network coverage is relatively narrow, but communication charges are very expensive, so I have been unable to get the actual application.

Today, with wireless mobile communication technology for the rapid development of wireless network based on GSM mobile communications technology is becoming increasingly sophisticated, further increasing the reliability of communication, network coverage was expanded, and a communication fee has also been considerable with telephone, or even lower.

Therefore, in the city fire alarm network communications using the GSM network should be practical. [1] [2] [3] [4] [5]