EMV contactless logo
The EMV contactless logo must appear on your machine panel at the same position as the logo printed on the UNO-mini device: the center of the antenna. When reproducing the logo, follow the EMVCo sizing, clear space, and color rules. See the EMVCo Contactless Symbol Reproduction Requirements for the full specification.Card scheme brand guidelines
Card scheme logos on the machine panel or display are optional. If you choose to display them, they must comply with each scheme’s brand guidelines. The following table lists the brand guidelines documentation for each major card scheme.| Card scheme | Brand guidelines |
|---|---|
| Visa | Visa Merchant Signage |
| Mastercard | Mastercard Brand Center |
| American Express | American Express Checkout |
| Discover | Discover Global Network Signage and Logos |
LED and audio requirements
The UNO-mini has 4 green LEDs on its front panel. These LEDs are required by EMVCo for POS devices and must be visible to the end user.
- Create a transparent area in the machine panel to expose the original device LEDs directly.
- Simulate the LED states on the machine display screen, if one is present.
LED and audio states
The following table lists all LED and audio states as defined in EMVCo Book A v2.10, sections 9.x. LED legend: ○ Off, ● On. Blinking states are noted in the LED pattern column. Audio tones:- Success tone: approximately 1500 Hz sine wave, 500 ms
- Alert tone: approximately 750 Hz double beep (200 ms on / 200 ms off / 200 ms on)
| Status | Msg index | Description | LED pattern | Message display | Audio |
|---|---|---|---|---|---|
| Not Ready | — | Reader not powered or not communicating | ○ ○ ○ ○ | No message | None |
| Idle | 17 | Powered and connected, not polling for card. First LED blinks approximately 200 ms every 5 s. | ● ○ ○ ○ (blink) | Welcome | None |
| Ready to Read | 1 | Polling for card. Transaction amount may be shown. | ● ○ ○ ○ | € xx.xx / Present card | None |
| Card Read Successfully | 35 | All four LEDs light in sequence over approximately 250 ms, then remain lit for approximately 750 ms, then turn off. Total duration: 1000 ms. | Sequential flash (all 4) | Card read OK / Remove card | Success tone |
| Authorizing | 36 | Online authorization in progress | ○ ○ ○ ○ | Authorizing / Please wait | — |
| Approved | 6 | Transaction approved by issuer or by terminal offline decision | ○ ○ ○ ○ | Approved | None (success tone played at card read) |
| Not Approved | 9 | Transaction declined by issuer | ○ ○ ○ ○ | Not Approved | Optional alert tone |
| Declined | 255 | General decline | ○ ○ ○ ○ | Declined | Optional alert tone |
| Read Error | 39 | Error occurred reading the card | ○ ○ ○ ○ | Read error / Please try again | Optional alert tone |
| Conditions Not Satisfied | 38 | Contactless conditions not met, for example when risk management requires a contact chip | ○ ○ ○ ○ | Please try another card | Optional alert tone |
| Contactless Collision | 5 | Multiple contactless cards detected simultaneously | ○ ○ ○ ○ | Present one card only | Optional alert tone |
| Timeout / No Card | 30 | Transaction timed out with no card presented | ○ ○ ○ ○ | Timeout / No Card | Optional alert tone |
| Terminated | 10 | Transaction terminated by terminal or application | ○ ○ ○ ○ | Terminated | Optional alert tone |
| PIN Entry Required | 11 | Card requires PIN entry, which cannot be performed via contactless | ○ ○ ○ ○ | Please try another card | Optional alert tone |
| See Phone | 12 | Mobile device requires customer action, such as unlocking or approving on the phone | ○ ○ ○ ○ | See Phone | Optional alert tone |
Next steps
Power Supply
Review power requirements and wiring recommendations before connecting the device.
Connection Interfaces
Connect the UNO-mini to your host controller via USB or UART TTL.