Please help with Teltonika protocol support for FM4200 devices. Detailed description below
When you first connect a device, the server downloads some of its settings. in log - “the command to request or change the setting has been sent” This causes a lot of problems with Teltonika FM4200 devices.
With each connection and sending the AVL packet by the device, an attempt is made from the server side to download the parameters - unfortunately during this (unsuccessful) attempt server accepts AVL data but does not confirm this fact, what the device close the connection without erasing the data from FLASH.
Device log when AVL data is sending and server tries to request settings from device
-[2021.9.1 17:53:47]-[DATA.SEND.TCP]->Server Answer Received
-[2021.9.1 17:53:47]-[DATA.SEND.TCP]->Scheduler Tasks Deleted
-[2021.9.1 17:53:47]-[DATA.SEND.TCP]->Invalid Server Response:  Expected: 
-[2021.9.1 17:53:47]-[DATA.SEND.TCP]->Deleting TCP Data Transfer Task
-[2021.9.1 17:53:47]-[APP.SEND.DATA]->Data Transfer Task finished. Closing Link…
-[2021.9.1 17:53:47]-[APP.SEND.DATA]->Closing Link…
With proper operation, it should be like this:
-[2021.9.1 17:57:34]-[DATA.SEND.TCP]->Server Answer Received
-[2021.9.1 17:57:34]-[DATA.SEND.TCP]->Scheduler Tasks Deleted
-[2021.9.1 17:57:34]-[DATA.SEND.TCP]->AVL DATA accepted
-[2021.9.1 17:57:34]-[DATA.SEND.TCP]->Deleting Sent AVL Records from FLASH memory…
There are quite a lot of attempts to request each parameter from the device. As a result, with each new connection, the device sends more and more AVL data from memory because due to the invalid server response, AVL data is not cleared from FLASH after sending.
After some long time, (c.a. 2 hours) the counter of attempts to request settings from the device defined by you is reached ( in toolbox log I can see: the system marked the setting as unreadable due to exceeded retries limit) and after that the device connects to the server in a correct way without closing link after every AVL package, server sending valid response after AVL package is received and finally device buffer is cleared - everyfing working.
Unfortunately, this action when server trying to download device settings causes more GPRS data consumption and delays associated with the transfer of ever larger AVL packages.
Question 1. Why are there so many attempts to download each parameter if the device does not provide it. Some time ago this problem did not occur so something had to change.
Question 2. Is it not possible to disable parameter retrieval for Teltonika FM4200 devices at all ?
Currently, most of these devices do not support accepting commands sent by GPRS at all (SMS only)
In older versions of firmware GPRS Commands ware supported, however, after the event GPS week number rollover Teltonika released and published new patched firmware because a lot of FM4200 devices have completly stopped working. New firmware does not have support for GPRS commands. I think they are unlikely to improve it, couse devices FM4200 are EOL