GSM-Modem

A Python GSM modem implementation based on the SIM868 specification

API Summary

Method	Description	Arguments	Hayes Commands
write	Send a Hayes command to the modem	command, timeout = 5
read	Reads a response from the modem
getEcho	Get an echo response from the modem		AT
getCSQ	Get the call signal quality		AT+CSQ
getText	Get an SMS text message from the modem		AT+CMGR
sendText	Send an SMS text message	number, message	AT+CMGF=1 AT+CSCS="GSM" AT+CMGS
setGPSOn	Turn the GNSS/GPS on		AT+CGNSPWR=1
getGPSData	Get the GNSS/GPS data from the modem		AT+CGNSINF
httpPost	HTTP post to a url	url	AT+HTTPINIT AT+HTTPPARA AT+HTTPACTION=0 AT+HTTPTERM
httpInit	Initialize the HTTP client		AT+HTTPPARA="CID",1 AT+SAPBR=3,1,"CONTYPE","GPRS" AT+SAPBR=3,1,"APN","pp.vodafone.co.uk" AT+SAPBR=3,1,"USER","wap" AT+SAPBR=3,1,"PWD","wap" AT+SAPBR=2,1 AT+SAPBR=1,1

getCSQ

Value	Definition
0	-115 dBm or less
1	-111 dBm
2...30	-110... -54 dBm
31	-52 dBm or greater
99	not known or not detectable

sendText

The number argument takes phone numbers in the E.164 format, for example +447797123456

setGPSOn

The method only needs to be called once to turn the GNSS/GPS functionality on

getGPSData

The method returns a string-indexed array. The keys are datetime, latitude, longitude and altitude

httpInit

The method only needs to be called once to initialize parameters for future HTTP interactions. The modem is configured to use Vodaphone UK's configuration; this can be easily changed via the modem code

Examples

The below example opens a serial connection to the modem via COM3, prints an echo response from the modem, prints the current call signal quality, turns the GNSS/GPS on and then prints the GNSS/GPS data to the console every 60 seconds

def main():
	modem = GSMModem('COM3')

	print("Echo = " + modem.getEcho())
	print("CSQ = " + modem.getCSQ())

	time.sleep(1)

	modem.setGPSOn()

	while True:
		gps = modem.getGPSData()

		print("GPS Data = " + str(gps))

		time.sleep(60)


if __name__ == '__main__':
	main()