TransCore 05531 User Manual

If the Encompass 4/4800 Multiprotocol Reader  receives an illegal command, it 
returns its standard Error message.

If the Encompass 4/4800 Multiprotocol Reader  transmits an asynchronous message 
and the host does not send an ACK

before the ECP timeout occurs, the Encompass 4/

4800 Multiprotocol Reader  retransmits the message.

If the Encompass 4/4800 Multiprotocol Reader  receives a 

but does not receive 

a matching 

before the ECP timeout occurs, it discards the incomplete message 

and resets its receiver.

If the Encompass 4/4800 Multiprotocol Reader  transmits asynchronous data at the 
same time that the host sends a command, the Encompass 4/4800 Multiprotocol 
Reader  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.

If the host detects an incorrect CRC value in a reader message, it retransmits the com-
mand with the same sequence number. If the host detects an incorrect CRC value in an 
asynchronous reader transmission, it transmits a NAK

message.

If the Encompass 4/4800 Multiprotocol Reader  does not respond to a host command 
within a specified interval, the host software retransmits the command with the same 
sequence number.

If the host receives a

but does not receive a matching

within a specified 

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