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Transmission Methods
A block with 700 bytes of user data is to be transmitted. For this purpose, the block is divided into three frames:
1
st
frame:
5A CD 50 02
— 200 bytes of user data follow — P1 P2
2
nd
frame:
5A FF 50 01
— 250 bytes of user data follow — P1 P2
3
rd
frame:
5A FF 50 00
— 250 bytes of user data follow — P1 P2
The receiver can use the fr
ame number of the first fr
ame (here
02
) and its length byte to calculate the block size (block
size = frame number * 250 bytes + length byte -5) (here in the example: 2 * 250 bytes + 205 bytes - 5 bytes = 700 bytes),
and reserve an appropriate amount of memory for the data.
User Data
User data are the bytes in a fr
ame that flow into the block tr
ansmitted.
Checksum
The checksum is calculated using the polynomial x^16 + x^12 + x^5 + 1 with a pre-initialisation of 0x0000 from the start
code to the last user data byte.
Network Layer
As the KBRP is a point-to-point protocol, there is no network layer.
Transport Layer, Session Layer, Presentation Layer,
Do not exist.
Application Layer
The application layer transmits data blocks from 1 to a maximum of 64000 bytes.
11.2
LLRP Protocol
Based on the TCP communication protocol, the Kathrein RFID reader with the Linux operating system can handle the
so-called
Low Level Reader Protocol
(LLRP).
It is a communication interface between an RFID reader and a LLRP-enabled application software standardised by
EPCglobal
(
http://www.epcglobalinc.org/standards/llrp
). The default port for LLRP is 5084.
The LLRP protocol is roughly divided into the following parts:
●
Automatic query of the reader functions via the application software
●
Configur
ation of the reader functions via the application software
●
Triggering of read and write operations on the air interface voa the application software
●
Transfer of the found tag data to the application software
To start the LLRP application, use the
AppManager
of the
ReaderStart
. In the menu, it is possible to load the LLRP protocol
engine by means of
Install App
and start it using
Start App
.
To test the Kathrein reader with the LLRP protocol, it is possible to use the open-source programming tool
Eclipse (IDE)
. By
means of the so-called
LLRP Commander
it is possible to control and operate the reader.
Eclipse (IDE)
and
LLRP Commander
are not part of the Kathrein RFID software.
