Send pass payload using OSDP over an RS-485 interface

The OSDP interface allows mobile NFC pass card and tag payloads to be passed straight to an access controller, like data from any other access control card reader. To enable an OSDP interface you will need to make changes to the config.txt file.

Note: You can use OSDP on any serial interface. Here it is assumed you are using OSDP over a Serial2 RS-485 interface, as this is the most common scenario, creating an RS-485 OSDP connection between a reader and door controller. To use OSDP on a different interface just substitute Serial2... in the examples for Serial... or COMPort...

  1. First ensure that the Serial2 interface is enabled as an RS-485 interface.

    Copy 
    Serial2RS485=1
    Serial2Settings=9600,n,8,1 ; this is the default - but must match
                               ; required interface speed
    Serial2Source=A1

    Here Serial2RS485=1 sets the Serial2 interface to behave as an RS-485 interface. Serial2Source=A1 is the default setting to ensure that interface will send data from all passes and cards/tags that can be read. And Serial2Settings=9600,n,8,1 ensures that the interface speed used by the VTAP reader matches that expected on the RS-485 interface.

  2. Then add settings to allow the Serial2 interface to follow OSDP.

    Copy 
    ; Essential settings
    Serial2OSDP=1
    Serial2OSDPAddress=0
                                        
    ; Settings for secure channel mode
    Serial2OSDPKeySlot=3
    Serial2OSDPSecureOnly=0 ; use =1 if you need to enforce secure channel

    ; Other options                                    
    Serial2OSDPFormat=Wiegand ; use =Wiegand or =ASCII credential format

    These settings in config.txt, are specific to control the transfer of data using OSDP:

    • Serial2OSDP enables or disables use of OSDP on the Serial2 interface.

    • Serial2OSDPAddress gives the VTAP reader a numerical address 0 to 126, as a peripheral device under OSDP.

    • Serial2OSDPKeySlot points to any one of the 9 available application key slots, loaded by providing a file such as appkey3.txt, as the one to be used to hold the OSDP Secure Channel Base Key.

    • Serial2OSDPFormat can either be set to ASCII or Wiegand (raw), where the output will be a binary number comprised of a bit count and bit stream. In Wiegand format the other Wiegand... settings will determine how that data is formatted, for example setting the bit length and format for pass and tag data. (See Wiegand interface settings for more detail.)

    • Serial2OSDPSecureOnly can be used to require that only the Secure profile is used, after initialisation. If this is not done, it is possible that the implementation of OSDP on the controller would allow its PDs to fall back to using the Basic profile if Secure credentials failed.

  3. After making the necessary changes to your config.txt file and saving it, you can connect the VTAP100 to your access controller. You can leave other USB or serial connections in place at the same time, if you want to test the configuration before disconnecting.

    Passes will then be read by VTAP100 with data passed direct to your access controller using OSDP.

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