Roche Cobas C 311 - Receiver Sends Characters Other than

Roche/Hitachi cobas c 311 analyzer ASTM communication protocol
Definition of Communication Protocol
Roche Diagnostics May 2011
Host Interface Manual – Version 1.3 D-5
Fig D-1 Establish phase
Normal procedure of Establish phase is mentioned above. In
case of error, there are additionally three options for the
receiver to respond [ENQ].
(1) Receiver sends characters other than [ACK].
These characters are normally sent by using ASCII code
15hex [NAK] when the receiver is busy. The sender waits for
a certain length of time, e.g., cobas c 311 analyzer waits for
10 seconds, and tries to establish with the other [ENQ]. The
cobas c 311 analyzer repeats this cycle until the number of
retries after error reaches six.
(2) Sender sends [ENQ].
The status in which both sender and receiver are trying to
change their status to the sender is called “Link contention” in
ASTM. When in link contention, it is defined that
communication information of cobas c 311 analyzer has a
priority. So that HOST has to stop sending [ENQ] and has to
respond simultaneously by [ACK] or [NAK] when the link
contention is detected. On the other hand, the cobas c 311
analyzer waits for more than 1 second and replies [ENQ].
The sender repeats this cycle until receiving characters such
as [ACK] or [NAK].
(3) No response from receiver.
The sender starts Termination phase by sending ASCII code
04hex [EOT] after waiting for 15 seconds, and displays an
error message.
ENQ
XXX
ENQ
ENQ
ENQ ENQ ENQ
A
C
K
10sec
Retry
Retry Retry
1sec 15sec
Establish phase Transfer phase
Sender
Receiver
(1) (2)
(3)