+CMS ERROR: 513
There are 3 possible causes for getting a +CMS ERROR: 513
The MS (jindi sms modem) loses the radio link (or the network requests an RR disconnect)
The MS (jindi sms modem) does not receive the acknowledge from the network (CP_ACK) about 28s after the transmission of the Short Message data (CP_DATA)
The MS (jindi sms modem) does not receive the acknowledge from the network (CP_DATA(RP_ACK)) about 42s after the channel establishment request