User Manual Part 2

RFID Interface
154
LRP820S-Series Long-Range Passive Reader/Writers
6.7 ABx ASCII Protocol Response Structure
Field
Number of ASCII
Characters
Content
Header 2 <STX><STX>
(02H, 02H)
response Size 4 Packet length in bytes excluding the header,
Command size, checksum and terminator
bytes.
Command 2 Command Echo
(Data) variable response data
Checksum 2 Optional Checksum
Terminator 1 <ETX> (03H)
If the controller encounters a fault it will respond with the following:
6.8 ABx ASCII Protocol Response Structure
Most RF operations will also require additional parameters and data
that will be included in the command stream between the command
code or echo and the terminator. The Header and Terminator are
always STX and ETX respectively. Any other field value is in ASCII
hex notation. Allowed values: '0'-'9', 'A'-'F'. Example: the value ABH
(decimal 171) in ASCII protocol is transmitted as a 2-character string
«AB», i.e. the 2 bytes: 41H 42H (ASCII values for 'A' and 'B'). The hex
Field
Number of
ASCII
Characters
Content
Header 2 <STX><STX>
(02H, 02H)
response Size 4 Packet length in bytes excluding the header,
Command size, checksum and terminator
bytes.
Error Flag 2 FFH
Error Code 2 Hex error code, see Table 11 for details
Checksum 2 Optional checksum
Terminator 1 <ETX>(03H)