Marantz SR7002 - Manual (Page 7)

SR8002/SR7002
RS-232C Control Specification
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3-3. The transaction sequences and the regulations
3-3-1. The transaction sequences
The transactions have three kinds of sequence.
*A transaction is a Command from Host then Slave will be an answer by Status answer, ACK or NAK.
*A transaction is a Status request from Host then Slave will be an answer by Status answer or NAK.
*A transaction is Auto status feedback from Slave when a Slave’s status changed. (If the auto status
feedback is enabled.)
3-3-2. The transaction regulations
The transactions have some kinds of regulation.
* An answer (ACK, NAK or Status answer) transmittion by Slave has to finish within 500ms when got a
Command or a Status request from Host.
* Host must not transmit an another Command or Status request until "it receives a answer by a
previous Command or Status request" or "it passes a term of waitinng time from a finishing of previous
transmission of a Command or a Status request ".
* Slave has to finish a transaction under 500ms when it sends Auto status feedback data.
3-3-3. Specification of Auto status feedback
There are some specific regulations about Auto status feedback.
* The product status has segmented into four layers of 1, 2, 3 and 4.
* The status of layer 1 are assigned most kindly status to Host. (The statuses of layer 2 are assigned
kindly status, the statuses of layer 3 are not so need status to Host and the statuses of layer 4 are
probably no wished statuses.)
* Each layer status can control transmit enable or disable by Host command. (The product default
would be all disables.)
* Slave sends auto status feedback by itself when the status is changed and if the status feedback is
enabled.
* The product defined and segmentationed layers are takeing in status list.
3-3-4. Example of the transactions
<Host> <Slave>
TxD RxD
RxD TxD
Example of the transactions
Max. 0.5sec
Transaction Transaction
Command
Status answer
ACK or NAK
Status
request
Status answer
Max. 0.5sec