User's Manual

Page 5
ISO In : The host sends a command + data and receives the status words.
ISO Out : The host sends a command and receives data + the status words.
Coupler with firmware former than 40-017F has only ISO NONE, ISO IN and ISO OUT protocol available.
In all cases, status words are returned (SW1 and SW2).
Case 1: ISO None Data Exchange
Command Status words
Host Class Ins. P1 P2 P3
Coupler SW1 SW2
nb. bytes 5 bytes 2 bytes
Case 2 : ISO Out Data Exchange - Coupler ð Host
Command Ack. Data Status words
Host Class Ins. P1 P2 P3
Coupler = Ins. Data SW1 SW2
Nb bytes 5 1 =P3 2
Class : always 80h
• Instruction : command code
• P1 & P2 : command parameters
• P3: number of data bytes expected from the coupler
Ack. : coupler acknowledgement. It is always equal to the command code, except when an error occurs. If
the Acknoledgement value is different than the instruction byte, then the received byte is the first byte of a
status error code coded on 2 bytes.
Data : data sent to the host by the coupler. Size of the command has to be P3.
Status word : 90 00h if correct, error code.
Case 3: ISO In Data Exchange - Host ð Coupler
Command Ack. Data Status words
Host Class Ins. P1 P2 P3 Data
Coupler = Ins. SW1 SW2
Nb bytes 5 1 =P3 2
Couplers - Reference Manuel V1.3