A shared repository to provide a description of reverse-engineered glucometer protocols

View the Project on GitHub glucometers-tech/glucometer-protocols

FreeStyle Freedom Lite / Lite / Mini

Reverse Engineered by Alexander Schrijver) (@flupzor).

Important device notes

This protocol is used in the following devices:


These devices connect to a computer with a TRS (mini-jack) to RS232 cable.

Abbott provides a TIUSB3410 USB-to-Serial adapter by Texas Instruments. This cable is supported at least from Linux 3.14 and later.


Serial port configuration

The serial port should be configured as such:

Messages and commands

The FreeStyle protocol has 2 types of messages a command and a result. Currently only one command exists which returns multiple results.

generic-message = command / result

The host starts with setting up the connection. After that it should send the following command:

command = "mem"

The device then sends the following data.

result = CR LF
         serial-number CR LF
         software-version CR LF

serial-number = 7( ALPHA / DIGIT ) "-" 5( ALPHA / DIGIT )
software-version = CR LF 1*DIGIT "." 1*DIGIT *SP "-P"

The serial number is provided in the same format as other FreeStyle devices.

The software revision doesn’t seem to be very consistent. It usually includes a dot-version, as a normal software revision, and terminate with the -P string. Sometimes the version is space-padded, and sometimes it’s not.

Date and Time Format

currentdatetime = datetime

datetime = month SP day SP year SP time
month = "Jan " / "Feb " / "Mar " / "Apr " / "May " / "June" / "July" /
    "Aug " / "Sep " / "Oct " / "Nov " / "Dec "
    ; N.B. Except June and July all months have spaces at the end.
day = 2DIGIT
year = 4DIGIT

time = hour ':' minute ':' second
hour = 2DIGIT
minute = 2DIGIT
second = 2DIGIT


log = empty-log / log-contents
empty-log = "Log Empty END"
log-contents = CR LF
               nrresult CR LF LF
               resultline *(CR LF resultline)
               checksum "END"

nrresults = 3DIGIT; e.g. 001 or 250

resultline = result-value datetime2 plasmatype "0x00"
result-value = 3DIGIT
datetime2 = month SP day SP year SP time2
time2 = hour ':' minute
plasmatype = 2DIGIT

checksum = "0x" 4HEXDIG

There is probably is a maximum number of results. At the moment we are guessing it is 450 which is the maximum the Abbott Precision Xceed can store. The minimum is 1

Note that the inconsistent spacing (including the additional LF) is intentional.

NOTE: result-value minimum and maximum are not known; comparing with other Abbott device, it’s possible that they use the constants HI and LO instead.

The checksum is a simple accumulation of the ASCII values of the characters, up until the 0x literal (excluded), including the CR LF terminations.