Trying to Multi-Communicate / Building the CRC and 7bit package.


I'm currently trying to build an application to control the dispensers through one serial port from a computer without investing in raspberry pi's or the router board.

I have been trying to decode your packet information and think im understanding it from start to end, alas i cant get the pump to respond to me no matter the binary commands i send or build.

I have been reading and following your code for the last 5 days thus far and been pinging the pump non stop to try and get any data back from her,

I understand that the packet information is 10 bytes long but not sure what escaped by 7 bits means... ( shifted over by 7 0's? ex 0000000? )

so i have been manually building the strings to try and attempt to get something back from it in terms of version but no luck so far.

your flow as documented is something along the lines of :

Final_Packet = "FF FF " + pack7.pack_7bit(packet + pack("<H", crc))

Final_Packet = "FF FF " + pack7.pack_7bit("3C 42 42 49 FC 27 00 00 00 00" + pack("3C 48", crc)) //in this case the crc would be "3C 42 42 49 FC 27 00 00 00 00" converted using sites below "3C424249FC2700000000", string mode, crc16, w poly set to 0xA001 i belive....

so a packet of "3C 42 42 49 FC 27 00 00 00 00" has a crc of "4E82 "

before encode = FF FF 3C 42 42 49 FC 27 00 00 00 00 4E 82

nearFinal = FF FF 7bitpacked( 3C 42 42 49 FC 27 00 00 00 00 3C 48 4E 82 )


using the 7 bit sim / gsm site with no settings on, again retriving from ussd entry.


Final = FF FF B3214D4693D172C6A1EC0683C16030180C361BD270B4224E06

I send it the last command above and it only hangs and never sends me back a response whatso ever, any help would be appreciated. I know i have to be wrong somewhere in there at least once, sorry if so im trying my best to build this and understand it in python and daq atm.

CRC site :

7bitpackage site :, using the USSD entry as the result im assuming based on the length....

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