I need to connect a slave device with 4 mater devices. Slave device has only one RS-485 port. I need to poll data from this slave device by 4 master devices. Is there any device available that can be connected on RS-485 port of slave device to expand one RS-485 port of slave device to 4 Nos. RS-485 or RS-232 ports to send data to 4 master devices?