The empeg player should, by default, work on the ethernet plug. When you plug it into a properly-configured ethernet network and apply power to it, it should get a DHCP address And Just Work. So you can load music that way.
You cannot, however, upgrade its internal firmware without a serial port. If the player is not running the latest firmware (2.0 final is what you should be using), then you will want to do this as soon as possible. Also the popular Hijack Kernel can only be installed via the serial port the first time. And Hijack is very useful, so you also want a serial port so you can do this.
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