GO4 stores data using a fixed length structure (15 bytes) which contains speed, location, GPS time, ignition on/off state and auxiliary states. In addition there is also a message header and footer. The minimum packet size including the header and footer is 30 bytes.
An acknowledgement is also required to come back from the server. Depending on your communication medium, there will be additional overhead of the TCP/IP layer.
We have found empirically that it takes about 180 bytes to send 1 packet as per above, including the ACK from our server. This is on a typical GPRS network and could be different depending on how the TCP/IP settings are configured for that network. Its cost effective to send records in a batch, since the original payload increases by 15 bytes but the overhead remains the same. |