User Manual

September 2001 S6350 Reader Reference Guide

3.1 Serial Protocol Definition

The S6350 reader accepts and sends data at RS232 levels, 57600 baud, 8 data bits, 1 start bit,

1 stop bit and no parity. The data packet from the host to the reader is known as the request

and the reply from the reader to the host as the response. The host is always the primary station

and initiates all communication sequences. These consist of request/response pairs where the

host waits for a response before continuing. The S6350 reader does not use the node address.

3.1.1 Request Packet Format (Host to Reader)

Field Name SOF

Field Size 1 byte

Field Value 01

hex

Purpose Start of Frame

Field Name Length

Field Size 2 byte LSB first

Field Value Packet dependent

Purpose Describes the length of the whole packet including SOF

Field Name Node Address

Field Size 2 byte LSB first

Field Value 0000

hex

Purpose Must be 0000

hex

for upward compatibility

Field Name Command flags

Field Size 1 byte

Field Value Varies by command

Purpose Specifies the action to be taken by the reader

Field Name Command

Field Size 1 byte

Field Value Varies by command

Purpose Specifies the action to be taken by the reader

Field Name Data

Field Size 0 to xx bytes

Field Value Command dependent

Purpose Contains the parameters and data for the command

Field Name BCC

Field Size 2 bytes

Field Value 16 bit LRC of the preceding packet including the SOF

Purpose Allows the reader to validate the correct reception of the request

packet