Sending commands to a VTAP reader

You can send VTAP commands to perform various operations including:

Data requests, such as a command to retrieve the last pass or card/tag payload from the VTAP reader.
Remote management commands, to set any of the VTAP settings in the main configuration (config.txt), or retrieve any of the files stored on the VTAP reader, such as config.txt or boot.txt.
Dynamic configuration commands, to perform operations not saved in config.txt like enabling/disabling the NFC field to save power, or perform integration tasks, such as consuming newly loaded keys.

Any serial port (USB ComPort, RS-232, or RS-485 serial port) can be a Command Interface, if your VTAP reader hardware permits.

Note: The serial RS-232 interface is an option on VTAP50‑OEM and VTAP100‑OEM readers only. The serial RS-485 interface is an option on VTAP100‑PAC‑485‑CC readers only.

You can send the commands to the VTAP through any terminal emulator such as TeraTerm or PuTTY, or your own custom software.

Note: End any command sent with a <CR> or <LF>, but not both.

By default, with CommandInterfaces=7, sending commands is enabled on all available serial interfaces of the VTAP reader. You can change this value to restrict which interfaces can be used to send commands: CommandInterfaces=1 for USB ComPort only, =2 for Serial RS-232, and =4 for Serial2 RS-485. You add these values together to enable commands on multiple interfaces.

You might use the Command Interface on one communications port to control and configure the VTAP reader in passive mode, while receiving pass and tag data on a different port in active mode.

If you use the Command Interface on any serial port that is also set to receive pass or tag data, we recommend you enable passive mode. This avoids potential for confusion between command responses and pass or tag data. When a serial interface is set to use passive mode, your application will need to poll the VTAP reader (by sending an ?r command) to retrieve pass or tag data. This makes half-duplex operation possible (for example when using RS-485).

When developing your own software, use the data request commands to pull data from the VTAP reader, dynamic commands to make changes in VTAP reader behaviour to suit your system and connected hardware, and use remote management commands to modify config.txt if a setting is to be permanently changed in the VTAP reader.

The sections Data request commands, Dynamic commands and Remote management commands discuss the use of different types of commands, during integration or operation, over the ComPort, RS-232 or RS-485 interfaces.