Support Serial connection

[cl0rm]

The eISCP protocol can be used over serial(RS-232) and over ethernet.
Since This already wraps the ISCP commands in the eISCP frame format, it should be easy to modify this project to support the serial connection as well.

Useful for older AVRs and modern ones as well (because RS-232 works in Standby mode I think - ethernet needs a higher power level in standby, my NR-807 uses 50W+ in this standby mode.

Another option which I also consider (and might post on github) is to emulate eISCP with a WiFi module. In this case everything should work as the receiver is seen as an eISCP receiver by clients even though it communicates with ISCP over COM.

[cl0rm]

In case anyone is interested: I made an ESP8266 firmware that accomplishes exactly that.
https://github.com/cl0rm/eiscp_bridge
It should support eISCP and evem Auto-Discovery for every Onkyo/Integra AVR that comes with an RS-232 Port.

[ManiacDC]

Inspired by @cl0rm 's project, I've created an eiscp relay server. It works with the server connected directly to the receiver, or with the server connect to the receiver via a serial to ethernet server.

https://github.com/ManiacDC/eiscp-relay

I use this to connect to my Onkyo TX-SR805 from my phone using MyAV.