Global Positioning System (GPS)
•Grouped ‐ Reports held until the total is equal or greater than *PPSNFM which sets the packet size of grouped reports.
Store and Forward Reliable Mode
The Store and Forward Reliable Mode allows the PinPoint‐E to ensure all messages are received by the server even if the connection between them goes down for a period of time (such when a vehicle passes through a location where the cellular signal is weak or non‐existent).
With Reliable Mode, *PPSNFR, enabled, the PinPoint‐E will transmit a sequence number (1 to 127) as part of a packet of messages (may contain one or more reports). To reduce overhead, the server only acknowledges receipt of every eighth packet. The PinPoint‐E considers that 8 a “window” of outstanding packets.
If the PinPoint‐E doesn’t receive acknowledgement for a “window”, the modem will PING the server with a message containing the sequence numbers of the first and last packets that haven’t been acknowledged. The PinPoint‐E will continue until the server acknowledges receipt. When the PinPoint‐E receives the acknowledgement, it will advance its “window” to the next group.
When the PinPoint‐E is first powered on (or reset), it will send a Set Window message to sync up with the server for the current “window”.
On the other side, if the server receives an out of sequence packet, it will send a message to the modem noting the missing sequence and the PinPoint‐E will retransmit.
Figure 9-11: AceManager : PinPoint - *PPSNFR, *PPMAXRETRIES
Simple Reliable Mode will ‘give up’ after a configured number, *PPMAXRETRIES, of attempts and discard messages that cannot be transmitted or received after that number of tries.
Sending Reports Based on an Interval
You can configure the PinPoint‐E to send reports based on a time interval and/or on the movement of a vehicle (based on it’s position from one time to the next).
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Rev 3.0B Feb.08 |
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