Onkyo CR-N765 is a CD Receiver, i.e. a CD player with amplifier and support for line inputs, USB and network.

It can be controlled via network or by infrared signals. It has no RS-232 port.


Infrared codes seem to be standard Onkyo/Integra codes I have downloaded from this site (thank you!). They are NEC type (0051), device code D2.
Most codes I used have functions 03 or 04, but some have 05 or 09, so the codes in short form are:
0051 D2 04 XX
0051 D2 03 XX
etc.

Unfortunately, the device does not support discrete On/Off codes. These are [0051 D2 03 04] and [0051 D2 04 47] listed in the table; they do not work.
I scanned the whole range of 03, 04 and 05 functions, the only codes that bring the device from standby mode are:
0051 D2 04 CB - Power Toggle
0051 D2 03 91 - Eject (but it opens the tray)
0051 D2 03 1B - Play (turn on and play the CD)

The other potential problem is that input select commands are not entirely discrete: USB Input selects both Front USB and Rear USB, Digital input selects both Optical and Coaxial. So if you switch between different input types, the device remembers the previous settings; but if you emit same signal twice, you can switch to another input.


Network control is also available. The network protocol is also standard, it uses device type of 1 (Receiver).
E.g., a command to turn the device off:
"ISCP\x00\x00\x00\x10\x00\x00\x00\x08\x01\x00\x00\x00!1PWR00\x0d"

One problem is that the network interface takes some time to start. The device itself seem to take a few seconds to startup, but the 60128 port becomes available in 20 to 40 seconds after turning on.

The other problem is that the device does not support network wake-up. And so says the Onkyo application. After the device goes into standby, it can be turned on only either manually or by infrared commands - which are not discrete.

There is a dubious workaround for these problems: you can plug the USB flash stick into the front port, and enable USB charging is enabled in device settings. Then, in standby mode, the receiver will power the USB device, and, by some coincidence, the network interface will continue working. In this state, the device can be powered on by !1PWR01 command - but the USB drive must be plugged at all times.


The conclusion is: Onkyo CR-N765 is not very pleasant to control.