Reposting this as a little more concise description of my problem. I am seeking help in getting UDP data exchange working on HL7588 mini card over LTE. I can successfully configure UDP connection and send data to a test PC but I have not been able to receive a response data packet.
The following shows the exact AT command exchange I use between the controller and HL7588 mini card over serial interface (without HW handshaking). This is after GPRS network connection has been established and modem successfully receives a valid current date/time stamp from the data network. Comments are in parenthesis.
Rx: +KCNXCFG: 1,“GPRS”,“orbcomm.t-mobile.com”,"","",“IPV4”,“0.0.0.0”,“0.0.0.0”,“0.0.0.0”,0
Rx: +KCNX_IND: 1,4,1
Rx: +KCNX_IND: 1,1,0
Rx: +KCGPADDR: 1,“10.44.237.30” (Address returned varies but is usually constant for a long period.)
Rx: +KCNXCFG: 1,“GPRS”,“orbcomm.t-mobile.com”,"","",“IPV4”,“10.44.237.30”,“10.49.254.21”,“10.49.254.20”,2
Rx: +KUDPCFG: 1
Rx: +KUDP_IND: 1,1
Rx: +KUDPCFG: 1,1,0,4322,0,"",0,0
Tx: AT+KUDPSND=1,“18.104.22.168”,4322,16 (This is an example IP address only, not the actual address I use.)
Tx: 0123456789ABCDEF (UDP test application receives transmitted data packet of “0123456789ABCDEF”.)
(At this time embedded application waits for data. UDP test application sends single response data packets of “0123456789ABCDEF” to “10.44.237.30:4322”. Repeating this send action has no affect. I never see the “+KUDP_DATA…” notification described in UDP example of HL7588 AT Command Interface Guide.)
The last three received lines shown above always immediately follow “AT+KUDPRCV” command regardless of whether UDP data is sent or not sent from test PC. It is apparent to me that some parameter is incorrect or some crucial receive step has been missed. Any idea what I am missing or not doing correctly? Any help or suggestions would be greatly appreciated. Thanks in advance!