Individual Control
To control an indoor unit individually one RTD-NET interface is needed for each indoor unit.
Group Control
Up to 16 indoor units can be wired to the same RTD-NET (via the P1P2 network) - see page 5 of the attached RTD-NET installation instructions. In this case - 'Group Control' - any command from the RTD-NET is broadcast to all units within the same group.
Group data can be read from Holding and Input registers, and individual unit data can be read from Input registers (see the attached RTD-NET installation instructions for a list of available Modbus registers). See also this article.
P1P2 (Wired Remote Controller) Network
Up to two remote controllers are allowed on the P1P2 wired remote controller network. The RTD-NET acts as a wired remote controller. Therefore, only one additional wired remote controller is allowed in combination with the RTD-NET on the P1P2 network.