- ISO 15693
ISO 15693 is an ISO standard for "
Vicinity Card s", i.e. cards which can be read from a greater distance as compared toProximity card s.ISO 15693 systems operate at the 13.56 MHz
frequency , and offer maximum read distance of 1-1.5 metres.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).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 Theleast-significant bit s 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 kHzSubcarrier The data rate can be:Low 6.62 kbit/s ( fc/2048)
High 26.48 kbit/s ( fc/512)
A logic 0 starts with 8 pulses of 423.75 kHz followed by an unmodulated time of18.88 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 1and the end of a frame is:
# a logic 0
# 24 pulses of 423.75 kHz
# an unmodulated time of 56.64 µsThe data is 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 8 pulses of 423.75 kHz followed by 9 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 1and the end of a frame is:
# a logic 0
# 24 pulses of 423.75 kHz
# 27 pulses of 484.28 kHzThe data is sent using a
Manchester code .External links
* [http://www.waazaa.org/15693/ Final Committee Drafts in pdf form for free download]
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