Marantz SR7400 Surround Sound Receiver
- Great sounding receiver
- Crossover settings could go a little lower to better cater for small speakers
- Automation via its RS232 serial port
Automation
The SR7400 can be controlled via it's serial port. I have found this to be very reliable (much better than infrared) and the communication is two way, so you get an acknowledgement from each command you send plus you can poll its status (e.g. to read the current volume).
I control the receiver over my home network by connecting the SR7400's serial port to a Global Cache serial/network adapter
Serial Control Specification
As far as I can tell, this specification also applies to the SR8400 but I have not been able to test that.
Official Specification (source unknown): click here
The protocol file I use for my control software/driver: click here
Note that this specification is completely different to that for SR7500, SR8500, and SR5500. The spec for these receivers can be found here.
Serial Connection
A STRAIGHT THROUGH serial (NOT a Null Modem cable) is required since the SR7400 has its pins already reversed. The following connection parameters are required:
- Baud: 9600 bps
- Parity: None
- Stop Bits: 1
- Data bits: 8
- Flow Control: RTS/CTS (Hardware Flow Control) Note that software flow control and no flow control do not work so the connecting master device must support hardware flow control.
Marantz SR7400/SR8400 Control Software/Driver
Here is my Python driver for controlling the receiver over a local network with the receiver connected via its serial port to a Global Cache GC-100). You will also need the protocol file. When I have a chance I'll upload an example of how to use this.
Infrared protocol
Search for SR7400 on the Marantz USA support site.
