A direct RS-485 bus star wiring is not supported; star wiring requires the use of signal distributors.
Improper RS-485 bus star wiring
If star wiring is inevitable, EDA 997A RS-485 signal distributors may be used. The maximum system cable length can also be expanded by using these distributors, physically providing a new RS-485 bus with 1200 m cable length each at every distributor output.
Star wiring with RS-485 signal distributor
In case the maximum number of 32 bus participants is exceeded, the number of connected devices can be increased by using RS-485 distributors. Each distributor output physically provides one RS-485 bus which enables the additional connection of 31 further devices (the distributor output represents one bus participant itself).
The maximum system expandability depends on the RS-485 address range of the installed devices.
System expansion with RS-485 signal distributor
ATTENTION: The RS-485 signal distributor EDA997A is unidirectional! This means that the signal only flows from the input towards the outputs. Therefore, e.g. the interconnection of several keyboards is not possible with this signal distributor!