Samsung has been shipping full IP control models including Power On support since the 2016 models. Models prior to 2016 did not support Power On via network control. For information on whether your model supports full IP control, please consult Device Compatibility. For models that do not support full IP control, we recommend the use of an infrared adapter for Serial control (first choice) or IR control.
If your Samsung TV is EX-Link enabled, you may control it via serial via the use of a serial adapter and the Simple Cable Serial 3.5mm This method is the most full-featured choice.
For Samsung TVs that are not EX-Link enabled (typically old or low-end models), use IR control via an infrared adapter.