For my application, I need to know the mac address of emon.tx board, can someone tell me where to get access to it?
EmonTX doesn't have a network interface, so it doesn't have a MAC address either. Only EmonBaseRF has MAC address
If you meant the emonBase as mharizanov suggested, I find the easiest way is to give it an IP address usign DCHP. Your router should report the mac address once it's been assigned an ip.
You can also print it out serially from the emonBase. The mac address is stored here.
Open-source tools for energy monitoring and analysis. This project uses the GNU General Public Licence