OBID i-scan
®
System-Manual
ID ISC.MR/PR/PRH101
FEIG ELECTRONIC GmbH
Page 16 of 131
H60301-3e-ID-B.doc
2. Asynchronous Interface
2.1. Data Format and Protocol Frames
The Reader ID ISC.MR/PR/PRH101 can be configured by an asynchronous interface and data may be
written on Transponders or read from Transponders. The communication between Reader and con-
nected 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: Standard Protocol-Length (up to 255 Byte)
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
Protocol frame: Advanced Protocol-Length
Reader
←
Host
1
2
3
4
5
(6...n-2)
STX
(0x02)
MSB
ALENGTH
LSB
ALENGTH
COM-ADR
CONTROL-
BYTE
(DATA)
©
n-1
n
ª
MSB
CRC16
LSB
CRC16
Host
←
Reader
1
2
3
4
5
6
(7...n-2)
STX
(0x02)
MSB
ALENGTH
LSB
ALENGTH
COM-ADR
CONTROL-
BYTE
STATUS
(DATA)
©
n-1
n
ª
MSB
CRC16
LSB
CRC16
1
see ANNEX D: Index of Status Bytes
