ISO/IEC 15693

ISO/IEC 15693, is an ISO standard for vicinity cards, i.e. cards which can be read from a greater distance as compared with proximity cards. Such cards can normally be read out by a reader without being powered themselves, as the reader will supply the necessary power to the card over the air (wireless).

ISO/IEC 15693 systems operate at the 13.56 MHz frequency, and offer maximum read distance of 1–1.5 meters. As the vicinity cards have to operate at a greater distance, the necessary magnetic field is less (0.15 to 5 A/m) than that for a proximity card (1.5 to 7.5 A/m).

Example applications

  • Public library: books have a unique ID stored in them. Books can checked out or in by simply placing them in the range of a reader
  • Ski pass: each of those has a unique ID and the system knows for how long the pass is valid etc.

Communication to the card

Communication from the reader to the card uses an amplitude-shift keying with 10% or 100% modulation index.

The data coding is:

1 out of 4 pulse position modulation
2 bits are coded as the position of a 9.44 µs pause in a 75.52 µs symbol time, giving a bit rate of 26.48 kilobits per second. The least-significant bits are sent first.
1 out of 256 pulse position modulation
8 bits are coded as the position of a 9.44 µs pause in a 4.833 ms symbol time, giving a bit rate of 1.65 kbit/s.

Communication to the reader

The card has two ways to send its data back to the reader:

Amplitude shift keying

Amplitude-shift keying 100% modulation index on a 423.75 kHz subcarrier. The data rate can be:

  • Low 6.62 kbit/s (fc/2048)
  • High 26.48 kbit/s (fc/512)

A logic 0 starts with eight pulses of 423.75 kHz followed by an unmodulated time of 18.88 µs (256/ fc); a logic 1 is the other way round. The data frame delimitors are code violations, a start of frame is:

  1. an unmodulated time of 56.64 µs (768/ fc),
  2. 24 pulses of 423.75 kHz
  3. a logic 1

and the end of a frame is:

  1. a logic 0
  2. 24 pulses of 423.75 kHz
  3. an unmodulated time of 56.64 µs

The data are sent using a Manchester code.

Frequency shift keying

Frequency-shift keying by switching between a 423.75 kHz sub carrier (operating frequency divided by 32) and a 484.25 kHz sub carrier (operating frequency divided by 28). The data rate can be:

  • Low 6.67 kbit/s (fc/2032)
  • High 26.69 kbit/s (fc/508)

A logic 0 starts with eight pulses of 423.75 kHz followed by nine pulses of 484.28 kHz; a logic 1 is the other way round. The data frame delimitors are code violations, a start of frame is:

  1. 27 pulses of 484.28 kHz
  2. 24 pulses of 423.75 kHz
  3. a logic 1

and the end of a frame is:

  1. a logic 0
  2. 24 pulses of 423.75 kHz
  3. 27 pulses of 484.28 kHz

The data are sent using a Manchester code.

Manufacturer codes

see ISO/IEC 7816-6

  1. Code 0x01: Motorola
  2. Code 0x02: ST Microelectronics
  3. Code 0x03: Hitachi
  4. Code 0x04: NXP Semiconductors
  5. Code 0x05: Infineon Technologies
  6. Code 0x06: Cylinc
  7. Code 0x07: Texas Instruments Tag-it™
  8. Code 0x08: Fujitsu Limited
  9. Code 0x09: Matsushita Electric Industrial
  10. Code 0x0A: NEC
  11. Code 0x0B: Oki Electric
  12. Code 0x0C: Toshiba
  13. Code 0x0D: Mitsubishi Electric
  14. Code 0x0E: Samsung Electronics
  15. Code 0x0F: Hyundai Electronics
  16. Code 0x10: LG Semiconductors
  17. Code 0x16: EM Microelectronic-Marin
  18. Code 0x1F: Melexis
  19. Code 0x2B: Maxim
  20. Code 0x33: AMIC
  21. Code 0x44: Nundlab, INC. USA
  22. Code 0x45: Nundnet by Nundlab, INC. USA

Implementations

The first byte of the UID should always be 0xE0.

Products with ISO15693 interface

  • EEPROM: various manufacturers like ST Microelectronics or NXP offer EEPROMs readable via ISO15693
  • µController: Texas instruments offers a small µController entirely powered by the ISO15693 reading field and capable of reading a simple temperature sensor, wirelessly providing the value of that to the reader
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