TCP/IP testing with Simcom SIM7070/SIM7080 Modules


Steps to test TCP/IP with SIM7070 and SIM7080 Modules

  • Verify that the device is registered with the network provider
  • Verify that APN is assigned using  the AT+CGNAPN command
  • Activate the network using the AT+CNACT command
  • Configure the device for TCP connection using the AT+CNCFG command
  • Open a TCP connection to the remote server using the AT+CAOPEN command.
  • Send TCP data using the AT+CASEND command
  • Get the response from the remote server using the AT+CARECV command.

AT Command Tester Tool provides an interface to test the TCP connection with the Simcom modules.

In this example,

  • TCP connection is made to remote server ‘postman-echo.com’
  • HTTP formatted data is sent to the remote server
  • The remote server echos the IP address of the device which is received by the module.

TCP Testing in script mode

TCP function can be tested with script mode in the AT Command Tester tool.

Try the script in AT Command Tester tool. 

//Script: TCP testing with SIM7070/SIM7080 modules
//Check SIMCOM Module AT Command documentaiton

//Get the current TCP configuration
AT+CACFG?

//Wait
WAIT=1

//TCP/UDP wait time
AT+CACFG="TRANSWAITTM",5

//Wait
WAIT=1

//TCP/UDP packet size
AT+CACFG="TRANSPKTSIZE",1024

//Wait
WAIT=1

//TCP/UDP timeout
AT+CACFG="TIMEOUT",0,10

//Wait
WAIT=1

//Activate the network
AT+CNACT=0,1

//Wait
WAIT=5

//Open TCP connection
//CID, PDP Index, connection type, server address, port
AT+CAOPEN=0,0,"TCP","postman-echo.com",80

//Wait
WAIT=5

//Send
AT+CASEND=0,46

//Send HTTP get as the TCP data
GET https://postman-echo.com/ip HTTP/1.0

//Wait for response
WAIT=5

//Get the response from the remote server
AT+CARECV=0,500

//Wait for response
WAIT=3

//Close the connection
AT+CACLOSE=0

Output of the script in the AT Command Tester tool. 

AT+CACFG?

+CACFG: TRANSWAITTM,2

+CACFG: TRANSPKTSIZE,1024

OK
AT+CACFG="TRANSWAITTM",5

OK
AT+CACFG="TRANSPKTSIZE",1024

OK
AT+CACFG="TIMEOUT",0,10

OK
AT+CNACT=0,1

OK

+APP PDP: 0,ACTIVE
AT+CAOPEN=0,0,"TCP","postman-echo.com",80

+CAOPEN: 0,0

OK
AT+CASEND=0,46

> 
OK

+CASEND: 0,0,46

+CADATAIND: 0

+CASTATE: 0,0
AT+CARECV=0,500

+CARECV: 351,HTTP/1.1 200 OK

Date: Sun, 21 Jun 2020 15:53:47 GMT

Content-Type: application/json; charset=utf-8

Content-Length: 22

Connection: close

ETag: W/"16-oWgnR5OcW0cDXWFy//pdWkFPX5Y"

Vary: Accept-Encoding

set-cookie: sails.sid=s%3ASdk9zJoskd7lyjdQqqL1KXCTZfHOdI7e.A0fAwOW7CSujaLee93RvJkFEVCrQUnXQn6G082bheNw; Path=/; HttpOnly



{"ip":"54.244.63.216"}

OK
AT+CACLOSE=0

TCP connection is closed by remote server

OK
Keywords: Module , M2M , GPRS , 3G , through AT commands,