Rdr_to_sph_trackdata – ACS ACR31 Swipe Card Reader User Manual
Page 15
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ACR31 – Reference Manual
Version 1.00
www.acs.com.hk
Page 15 of 19
6.8. RDR_to_SPH_TrackData
This message is sent by ACR31 when it detects the swiping of card and transfers Track 1 and Track 2
data to the mobile device.
There is no need for the mobile device to send any command message to ACR31 to retrieve the card
data. This message is sent automatically from ACR31 to the mobile device once a card swipe action
is performed and thus is known as an interrupt message.
Offset
Field
Size Value
Description
Encrypted
0
bStartByte
1
23h
Message start byte.
No
1
wLength
2
Number of extra bytes starting
from the next field for this
message.
3
bMessageType
1
50h
4
abTrack1Data
79
Magnetic stripe card track 1
data.
Yes
83
abTrack2Data
40
Magnetic stripe card track 2
data.
123
bFieldSeparator
1
0Dh
124
bTrack1DataLength
1
Effective data length or error
code.
If the MSB is set, It is an error
code. Otherwise, it is data
length.
125
bTrack2DataLength
1
Effective data length or error
code.
If the MSB is set, It is an error
code. Otherwise, it is data
length.
126
abRFU
4
Reserved for future use.
130
wChecksum
2
CRC16 checksum for data
starting from offset 4 to 129.
132
bFieldSeparator
1
0Dh
No
133
bLowVoltageDetector
1
Detect the power of Battery
00h – Not enough power
01h – Enough power
134
bTrack1Error
1
Track 1 error register.
If the MSB is set, It is an error
code. Otherwise, it is data
length.