yamaha

Yamaha Receiver Serial Control Ruby Library

Protocol Notes

RX-V1500 Power Values

You might expect the power state to be a bit field, but it isn't - each combination is assigned an independent value:

Main zone	Zone 2	Zone 3	Value	Notes
On	On	On	1	All on
On	On	Off	4
On	Off	On	5
On	Off	Off	2
Off	On	On	3
Off	On	Off	6
Off	Off	On	7
Off	Off	Off	0	All off

Implementation Notes

In order for the receiver to respond, the RTS bit must be set on the wire. Setting this bit requires a 5-wire cable. I have some RS232 to 3.5 mm cables which aren't usable with Yamahas.

Linux appears to automatically set the RTS bit upon opening the serial port, thus setting it explicitly may not be needed.

To monitor serial communications under Linux, I used slsnif which I found via this summary of serial port monitoring tools.

The receiver is very frequently not responding to the "ready" command. The documentation mentions retrying this command but in my experience the first time this command is sent to a RX-V1500 which is in standby it is always igored.

I have RX-V1500 and RX-V2500, however I couldn't locate RS232 protocol manuals for these receivers. I am primarily using RX-V1700/RX-V2700 manual with some references to RX-V1000/RX-V3000 manual. The commands are mostly or completely identical, with RX-V1700/RX-V2700 manual describing most or all of what RX-V1500/RX-V2500 support, but the status responses are very different. For my RX-V1500/RX-V2500 I had to reverse-engineer the status responses, and because of this they only have a limited number of fields decoded.

Volume level is set and reported as follows: 0 means muting is active, otherwise the minimum level for the zone is 39 and each step in the level is the next integer value up. For the main zone on RX-V1500/RX-V2500, the volume is adjusted in 0.5 dB increments from -80 dB to 14.5 dB, giving the integer values the range of 39-228. For zones 2 and 3 the volume is adjusted in whole dB increments from -33 dB to 0 dB, giving the integer range of 39-72.

While testing with Python, I ran into this issue - to open a TTY in Python, buffering must be disabled.

See here for more Yamaha-related software.

Other Libraries

Yamaha RS232/serial protocol:

• YRXV1500-MQTT
• YamahaController
• Homie ESP8266 Yamaha RX-Vxxxx Control

Serial port communication in Ruby:

• rubyserial
• Ruby/SerialPort

Helpful Links

• Serial port programming in Ruby