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^SIS URC indicating HTTP response | Telit Cinterion IoT Developer Community

September 7, 2015 - 2:53pm, 3006 views

Hello,

I am able to POST data using BGS2-W. Http is the type of internet service that I am using. I have enabled URCs. After writing all data using AT^SISW, I get a URC ^SISW:0,2 indicating that there is no more data that ***** to be transferred. Then I wait for ^SIS URC that indicates the result for the POST. When successful it contains ^SIS: 0,0,2201,"HTTP/1.1 200 OK". The time between writing the last chunk of data using SISW command and receiving 200 OK response is very dynamic. Sometimes I get the response in less than 100ms. Sometimes I dont get the response for 25 seconds. My application waits a certain time for the response and if it does not get the response, then it closes the connection and retries later. 

Could you please tell me the reason for the variation in the response time? Also I would appreciate if you could let me know how can the host application come to know whether it should wait for some more time before closing connection. 

AT command log (Http OK received 6 seconds after transferring the data):

20150907T090117 AT^SISS=0,hcContLen,8155

20150907T090117 OK 

20150907T090118 AT^SISS=0,address,http://testing.ibexis.net/ibexis-upload/data

20150907T090118 OK 

20150907T090118 AT^SISO=0

20150907T090118 OK 

20150907T090119 ^SISW: 0,1

20150907T090119 AT^SISW=0,1024

20150907T090119 ^SISW:0,1024,0

20150907T090120 1024 bytes sent

20150907T090120 OK 

20150907T090120 AT^SISW=0,1024

20150907T090120 ^SISW: 0,1024,0

20150907T090120 1024 bytes sent

20150907T090120 OK

20150907T090121 AT^SISW=0,1024

20150907T090121 ^SISW: 0,1024,0

20150907T090121 1024 bytes sent

20150907T090121 OK

20150907T090121 AT^SISW=0,1024

20150907T090121 ^SISW: 0,1024,0

20150907T090122 1024 bytes sent

20150907T090122 OK

20150907T090122 AT^SISW=0,1024

20150907T090122 ^SISW: 0,1024,0

20150907T090122 1024 bytes sent

20150907T090123 OK

20150907T090123 AT^SISW=0,1024

20150907T090123 ^SISW: 0,1024,0

20150907T090123 1024 bytes sent

20150907T090123 OK

20150907T090123 AT^SISW=0,1024

20150907T090123 ^SISW: 0,1024,0

20150907T090124 1024 bytes sent

20150907T090124 OK

20150907T090124 AT^SISW=0,987

20150907T090124 ^SISW: 0,987,0

20150907T090124 987 bytes sent

20150907T090125 OK

20150907T090125 ^SISW: 0,2

20150907T090131 ^SIS: 0,0,2201,"HTTP/1.1 200 OK"

20150907T090132 ^SISR: 0,1

20150907T090132 AT^SISR=0,255

20150907T090132 ^SISR: 0,17

20150907T090132 RN00=0~CRC=1234

20150907T090132 ^SISR: 0,2

20150907T090132 AT^SISC=0

20150907T090132 OK

The scenatio when SIS URC is not received after 25 seconds (timeout used in application), the log is the same till ^SISW:0,2 (No more data to send). After this nothing is received from modem for 25 seconds.

Please let me know your thoughts.