Question

I am testing RS232 function of FMC640. I generate data 222222222222222222222222222222222222, and send it through RS232 to FMC640. I can see FMC640 forward this data to our server using Codec 13.

When I enable and disable timestamp, in server side, the received messages are only 4 bytes difference.

enable timestamp 00000000000000320D01060000002A628AD0793232323232323232323232323232323232323232323232323232323232323232323232320D0A010000A56B

disable timestamp 000000000000002E0C0106000000263232323232323232323232323232323232323232323232323232323232323232323232320D0A010000C5FC

 According to the Codec 13 protocol, timestamp has 8 bytes, so it seems the message with enable timestamp is not correct.

Can you please check this issue?

Answer 1

Hi,

Kindly note that if the timestamp is enabled data will be sent via Codec 13 Protocol, otherwise if timestamp is disabled data will be sent via Codec 12 Protocol. In this case, the data received is correct.

You may check the Codec Protocol used on this byte as bolded below:

enable timestamp - 0D indicates Codec 13

00000000000000320D01060000002A628AD0793232323232323232323232323232323232323232323232323232323232323232323232320D0A010000A56B

For more information about Codec 13, kindly refer to this link: https://wiki.teltonika-gps.com/view/Codec#Codec_13

disable timestamp - 0C indicates Codec 12

000000000000002E0C0106000000263232323232323232323232323232323232323232323232323232323232323232323232320D0A010000C5FC"

For more information about Codec 12, kindly refer to this link: https://wiki.teltonika-gps.com/view/Codec#Codec_12

Hope this answers your question.

Regards!

Comments

Thanks. I know and understand enable timestamp will increase the length of the message. My question is the timestamp part is 8 bytes according to protocol Codec13, but in my test, there are only 4 bytes timestamp in FMC640 message.

00000000000000320D01060000002A628AD0793232323232323232323232323232323232323232323232323232323232323232323232320D0A010000A56B

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Hi,

Thank you for your feedback. For Codec 13 Protocol the timestamp is indeed has 4 Bytes only and not 8 Bytes.

Please refer to the data below:

The following diagram shows basic structure of Codec 13 messages:

0x00000000 (Preamble)	Data Size	Codec ID	Command Quantity 1	Type	Command Size	Timestamp	Command	Command Quantity 2	CRC-16
4 bytes	4 bytes	1 byte	1 byte	1 byte	4 bytes	4 bytes	X bytes	1 byte	4 bytes

For more information about Codec 13 Protocols, you may refer to this link: https://wiki.teltonika-gps.com/view/Codec#Codec_13

Regards!

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Thanks.

The reference I found indicates the Timestamp is 8 bytes for Codec 13. I think this reference has mistake.

https://wiki.teltonika-gps.com/view/Teltonika_AVL_Protocols#Codec_13