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→Codec 13 Nebaigta
!style="background: yellow; color: red;"| 0x01||Ignored bytes
!style="background: yellow; color: red;"| 0x01||Ignored bytes
|}
|}
<small>Figure 2. Structure of Codec 13 messages</small>
Structure explanation:
*'''Preamble field''' - four zero bytes.
*'''Data size field''' (size is calculated from:
<small>CID(0x0D = 1 byte)
NOD(0x01 = 1 byte)
CMD_TYPE(0x06 = 1 byte)
CMD_SIZE(variable = 4 bytes, includes size of timestamp field too)
PAYLOAD(variable size, stored in CMD_SIZE field)
NOD(0x01 = 1 byte))
</small>
*'''Codec ID field''' (in Codec 13 it is always 0x0D).
*'''NOD field''' (0x01, it is ignored when parsing the message).
*'''Message type field'''. It is always 0x06 since the packet is direction is FM->Server.
*'''Command size field'''. Command size field includes size of timestamp too, so it is equal to size of payload + size of timestamp.
*'''Timestamp field''' – UNIX timestamp (since 1970/01/01 00:00:00 UTC)
*'''Payload field''' – actual received data
*'''NOD field''' (0x01, it is ignored when parsing the message)
*'''CRC field''' – CRC-16-IBM
The algorithm to calculate CRC is CRC-16 (also known as CRC-16-IBM). All the fields from codec ID to last NOD field are used to calculate CRC. The algorithm of how to calculate CRC is shown in figure 3.
'''NOTE''' – Codec13 packets are used only when “Message Timestamp” parameter in RS232 settings is enabled.
[[Image:111.png|111.png]]
<small>Figure 3. CRC calculation algorithm</small>
*'''Command parsing example'''
The different fields of message are highlighted in gray and yellow for better readability.
Hexadecimal stream:
== '''<big>Codec 16 Nebaigta</big>''' ==
== '''<big>Codec 16 Nebaigta</big>''' ==
