OBID i-scan
®
System-Manual
ID ISC.M02.M8-B
FEIG ELECTRONIC GmbH
Page 9 of 43
H90400-0e-ID-B.doc
2. Asynchronous Interface
2.1. Data Format and Protocol Frames
The Reader ID ISC.M02.M8-B can be configured by an asynchronous interface and data may be writ-
ten on Transponders or read from Transponders. The communication between Reader and connected
host (terminal, PC, etc.) is executed by means of fixed protocols. The used protocol is intended for
data bus use and is equipped with a bus address.
During data transfer via the asynchronous interface the Reader supplies the required data or a status
byte. The reply contain the transmitted control byte.
There is no reply from the Reader if there is a protocol frame failure.
Protocol frame:
Host
→
Reader
1
2
3
4...n-2
n-1
n
LENGTH = n
COM-ADR
CONTROL-
BYTE
PROTOCOL-
DATA
LSB-CRC16
MSB CRC16
Host
←
Reader
1
2
3
4
(5...n-2)
n-1
n
LENGTH = n
COM-ADR
CONTROL-
BYTE
STATUS
1
(PROTOCOL-
DATA)
LSB-CRC16
MSB CRC16
LENGTH n:
Number of protocol bytes 1- n (6 - 255) incl. length byte and checksum
COM-ADR:
0..254 address of device in bus mode
Note:
The Reader can be addressed via COM-Adr 255 at any time!
STATUS / PROTOCOL-DATA:
Includes the status message or protocol data from or to the Reader. The data will be sent al-
ways as MSB first if the Reader is in the ISO15693Host Command Mode.
CRC16:
Cyclic redundancy check of the protocol bytes from 1 to n-2, as specified by CCITT-CRC16
Polynom:
x
16
+ x
12
+ x
5
+ 1 (0x8408)
Start Value:
0xFFFF
Direction: Backward
1
see ANNEX B: Index of Status Bytes
