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:
- an unmodulated time of 56.64 µs (768/ fc),
- 24 pulses of 423.75 kHz
- a logic 1
and the end of a frame is:
- a logic 0
- 24 pulses of 423.75 kHz
- 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:
- 27 pulses of 484.28 kHz
- 24 pulses of 423.75 kHz
- a logic 1
and the end of a frame is:
- a logic 0
- 24 pulses of 423.75 kHz
- 27 pulses of 484.28 kHz
The data are sent using a Manchester code.
Manufacturer codes
see ISO/IEC 7816-6
- Code 0x01: Motorola
- Code 0x02: ST Microelectronics
- Code 0x03: Hitachi
- Code 0x04: NXP Semiconductors
- Code 0x05: Infineon Technologies
- Code 0x06: Cylinc
- Code 0x07: Texas Instruments Tag-it™
- Code 0x08: Fujitsu Limited
- Code 0x09: Matsushita Electric Industrial
- Code 0x0A: NEC
- Code 0x0B: Oki Electric
- Code 0x0C: Toshiba
- Code 0x0D: Mitsubishi Electric
- Code 0x0E: Samsung Electronics
- Code 0x0F: Hyundai Electronics
- Code 0x10: LG Semiconductors
- Code 0x16: EM Microelectronic-Marin
- Code 0x1F: Melexis
- Code 0x2B: Maxim
- Code 0x33: AMIC
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
External links
- ISO/IEC 15693-1:2000 Identification cards — Contactless integrated circuit(s) cards — Vicinity cards — Part 1: Physical characteristics
- ISO/IEC 15693-2:2006 Identification cards — Contactless integrated circuit cards — Vicinity cards — Part 2: Air interface and initialization
- ISO/IEC 15693-3:2009 Identification cards — Contactless integrated circuit cards — Vicinity cards — Part 3: Anticollision and transmission protocol