Connect the PCB to a PC using either a MicroUSB to USB cable or the Optional captive cable connection - RS-232 and USB.

The VTAP50 is rated at 5V DC (typ. 110mA, max 150mA) for power over USB.

The VTAP50 must be stored and operated under the following conditions:

• Ambient temperature -25 to +70°C (-13 to 158°F)

• Humidity 0 to 95% RH non-condensing

• Pressure 86-106kPa

The PCB has 2.7mm diameter mounting holes for fixing the unit. Use 2-4 small nuts and bolts to mount the board securely.

The VTAP antenna should not be mounted more than 10mm deep within your enclosure (measuring from the antenna surface to the enclosure surface), so that a user’s smartphone will be able to come close enough to the antenna for reliable reading.

The antenna position should be clearly marked and easily accessed, so that users can position their smartphone appropriately. Be aware that antennas are positioned differently in different makes of smartphone. Apple iPhones often have antennas near the top and Android phones are more likely to have an antenna in the middle.

The PCB has a special connector J1 (an 8 pin, 2mm pitch header connector) which can be used to attach a captive cable with a matching crimp housing, for RS-232 or an alternate USB connection.

The standard connector fitted to the PCB, in most cases, is a Hirose DF11CZ-8DP-2V male header plug with shroud. The matching crimp housing is the Hirose DF11‑8DS‑2C.

The connector J1 includes both USB and RS-232 signals, as follows:

A PC or terminal RS-232 connector is usually DTE (data terminating equipment), typically a male DB9 with TXD on pin 3 and RXD on pin 2. The appropriate connecting cable is then a DCE (data communications equipment) female DB9. TXD and RXD pins are swapped between the DCE and DTE devices, so that the transmit pin on one connects to the receive pin on the other.

The VTAP50 requires a 5V power supply, but not all RS-232 devices have 5V on pin 9. Either:

• Disconnect the USB cable before making the serial connection, if power will be provided by J1 (pins 1 and 3) and the serial cable/host.

• Or retain a USB connection in addition to the serial connection, if power is not available from your RS-232 device.

Some serial cables have a separate DC 5.5/2.1mm barrel connector to supply power. In these cables, typically, the centre pin is +5V and the outer barrel is GND.

The FFC connector is found on the under side of the VTAP reader PCB.

Make a TTL 3.3V serial connection to pins 8 and 9 of the 12 way 0.5mm FFC connector:

Enabling the RS-232 serial port in your VTAP configuration will enable these TTL pins as well as the usual RS-232 interface.

The RS-232 serial interface on the main 8-pin connector is generally preferred because these TTL signals are not buffered and are not 5V tolerant, so must be used with caution, to interface with other 3.3V circuits only.

You can control and configure the VTAP through this serial RS-232 TTL interface, either by itself or while retaining the USB keyboard emulation output mode, which can be useful when testing. You can change the way the data is presented (eg with prefixes and postfixes) to suit your target receiving device/application.

The VTAP50 v1 board does not have feedback LEDs, which are present on the VTAP50 v2 board.

An external RGB LED can be configured to show a default colour permanently, and then automatically change colour (or flash) in response to a successful pass read, successful card read or other error conditions. This is done by changing the config.txt file. The external RGB LED can also be driven over a command interface.

On VTAP50 v2 boards with firmware from v2.1.11.2, a chain of serial LEDs can be connected to the serial LED connection on the expansion header. A chain of serial LEDs supports more complex LED options and requires a special leds.ini file to control their behaviour. This special configuration is explained in Control LED and buzzer feedback.

The expansion connector is not fitted as standard, but can be soldered in later.

Connect your external LED to the expansion header:

The external LED outputs are buffered 5V without any current limiting resistors, so you should attach a RGB LED board module that includes built‑in current limiting resistors. (We recommend 15mA per LED output at 5V, so the maximum current required is 350mA. External LEDs should be decoupled, with 10μF bulk capacitance per LED along the LED path) The VTAP50 can support both common cathode and common anode, by changing the LEDSelect setting in the config.txt file.

The VTAP50‑OEM has an option to snap off the on‑board antenna and connect an external antenna, with a suitable matching circuit, to the VTAP50 and VTAP100.

Dot Origin can provide support for integrating external off-the-shelf or custom NFC antennas with VTAP50 and VTAP100 readers. More detail is provided in VTAP Application Notes.

Attaching an external antenna uses the same expansion header as for external LEDs.

1. Snap off the VTAP50 and VTAP100 on‑board antenna. We recommend that you break the snap off points by applying pressure with a screwdriver, when the PCB is lying on a flat surface.

   

   Points on VTAP50 to snap off the on-board antenna.

2. Then connect the external antenna to the VTAP reader using the 10/12 pin expansion header via a matching or tuning circuit (see examples in Tune or match antennas). The pins 1 and 2 on the expansion header are used for external antenna connection.

   

   Expansion header to connect external antenna

   CAUTION: Always ensure sufficient clearance between the VTAP antenna and other RF transmitters to avoid electromagnetic interference between equipment. The clearance required varies from antenna to antenna, depending on antenna size, power and sensitivity.