Modbus RTU:
ModbusRTU is a serial communication protocol that connects different devices on the same network and would make the communication between them possible.
Modbus is transmitted over serial lines between devices. The cables used for the conecction are either RS-485 or RS-232 cables. The simplest setup would be a single serial cable connecting the serial ports on two devices, a Master and a Slave.
The data is sent as series of ones and zeroes called bits. Each bit is sent as a voltage. Zeroes are sent as positive voltages and ones as negative. The bits are sent very quickly. A typical transmission speed is 9600 baud (bits per second).
LonWorks:
LonWorks (local operation network) is a networking platform specifically created to address the needs of control applications. This platform is created for networking devices over media such as twisted pair, power lines, fibre optics, and RF. It is used for the automation of various functions within buildings such as lighting and HVAC see building automation.
There are two physical-layer signalling technologies, twisted pair "free topology" and power line carrier, are typically included in each of the standards created around the LonWorks technology. The two-wire layer operates at 78 kbit/s using differential Manchester encoding, while the power line achieves either 5.4 or 3.6 kbit/s, depending on frequency.
Additionally, the LonWorks platform uses an affiliated Internet protocol (IP) tunnelling standard in use by a number of manufacturers to connect the devices on previously deployed and new LonWorks platform-based networks to IP-aware applications or remote network-management tools. Many LonWorks platform-based control applications are being implemented with some sort of IP integration, either at the UI/application level or in the controls infrastructure.