Denon AVR-2311CI Service Manual page 52

(3) If connection is not good, then you can see the "Communication check NG" message.
Please confi rm the following
(a) Check the connection of the AV receiver/amplifi er and PC. (refer to "2.Connection of the AV receiver/amplifi er" )
(b) Check the operation mode of the AV receiver/amplifi er. (refer to "Turn on the AV receiver/amplifi er")
(c) Check the selection of the RS-232C port number of PC.
6. Download the fi rmware
(1) Click the "Load" button.
(2) Download the fi rmware from the specifi ed download source to PC.
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