ISO/IEC 15693, is an ISO/IEC standard for Contactless vicinity objects (vicinity cards and security devices ), i.e. objects 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). ISO/IEC 15693 is called contactless long-range standard with a lower RF speed compared to some other RFID standard such as ISO/IEC 14443.
The standard is developed by ISO/IEC JTC 1 (Joint Technical Committee 1) / SC 17 (Subcommittee 17) ..
Communication from the reader to the card uses an amplitude-shift keying with 10% or 100% modulation index.
The data coding is:
The card has two ways to send its data back to the reader. Both use a subcarrier transmitted back to the reader using load modulation.
Amplitude-shift keying 100% modulation index on a 423.75 kHz subcarrier. The data rate can be:
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 delimiters are code violations, a start of frame is:
and the end of a frame is:
The data are sent using a Manchester code.
423.75 kHzのサブキャリア(動作周波数を32で割った値)と484.25 kHzのサブキャリア(動作周波数を28で割った値)を切り替える周波数偏移変調 。データレートは以下のとおりです。
論理0は423.75kHzのパルスが8回続き、 その後484.28kHzのパルスが9回続きます 。論理1はその逆です。データフレームの区切り文字はコード違反であり、フレームの開始は次のとおりです。
フレームの終わりは次のようになります。
データはマンチェスターコードを使用して送信されます。
ISO/IEC 7816-6を参照