This document will guide you to understand the concept of the changed RS485 mode with BioStar 2.

RS-485 Mode

Three different RS485 modes are supported as below.

  • Default: Factory default status for a device configuration.
  • Master: Devices can search and add slave devices through RS485
  • Slave: Devices can be searched and added to a “Master” device through RS485


Mode TCP/IP Connection RS485 Slave Device Search Device Matching
Default OXO
Master OOO
Slave OXX

* Slave device is not making a device matching, and is just sending the credential input to a master device, and receiving the result and showing it from the indicator or LCD display.

Add a slave device

Change the RS485 mode to “Master”


Check the device mode. The “M” mark is shown before device IP address.

Move a mouse cursor to the master device, and do a right click.

Slave devices are searched and shown on the list, and mark a check-box and click “Add” button.

One master device can connect up to 31 devices, but up to 8 fingerprint devices are able to be connectable through RS485. We recommend minimum number of RS485 connected fingerprint devices considering the number of users and connected devices. This is because it can lead to slow matching speed depending on the device which is used for “Master” device.