13
Model No.
CRT-541
SPECIFICATION
Date
2010/01/10
Ver.
1.0
Card Dispenser
Page
10/16
5. General Communication Process
(1) After receiving correct data package, the unit will check the address. If
matched, unit must give positive answer to host: ACK+ADDRESS
(ADDRESS is the address of dispenser, 2 bytes); If not, unit can not send
any data to the host.
The unit gives negative answer if received error response or BCC error:
NAK+ADDRESS(ADDRESS is the address of dispenser, 2 bytes). If the
address is not matched, data package cannot be re-sent by unit.
(2) The host must re-send command package when connect with PC again
after receiving negative response.If it is still not correct after several
re-send, suggest the host alarm, and the user to check the
communication circuit.
(3) The host must not send nonexistent address number, otherwise, will not
receive any response message.
(4) The unit is subordinative to the host. Without receiving the command
from the host, I t will not send any data to the host.
