TransCore 05716 Manuel D’Utilisation

The MPRR addresses the following failure conditions.

If the MPRR detects an illegal sequence number in a host command message, it dis-
cards the received message and sends no response. If it receives an illegal sequence 
number in an ACK

message, it responds as if a NAK

had been received and retransmits 

the data.

If the MPRR receives the wrong sequence number in an ACK

message, it responds as 

if a 

 had been received, and it retransmits the data.

If the MPRR detects an incorrect CRC value in a host command message, it discards 
the received message. No response is sent. If it receives an incorrect CRC value in an 
ACK

 message, it responds as if a NAK had been received, and it retransmits the data.

If the MPRR receives an illegal command, it returns its standard Error message.

If the MPRR transmits an asynchronous message and the host does not send an ACK

before the ECP timeout occurs, the MPRR retransmits the message.

If the MPRR receives a 

but does not receive a matching 

before the 

ECP timeout occurs, it discards the incomplete message and resets its receiver.

If the MPRR transmits asynchronous data at the same time that the host sends a com-
mand, the MPRR gives priority to receiving the command. It processes the command 
and sends a message before it retransmits the asynchronous data.

The host computer addresses the following failure conditions.

If the host detects an illegal or wrong sequence number in a reader response, it retrans-
mits the command with the same sequence number. If the host detects an illegal 
sequence number in an asynchronous reader transmission, it sends a NAK

message.