Check Sum HDLC calculation

Hi

I am not able to calculate check sum for below massages, I will be appreciated if you can tell how they get this checksum (I even try crc calculator) and how can we write a code for it .

example 1: Checksum: 30 7E0511BF07307E

example 2:

Checksum 71 7E0611BF1704717E

Thank you

Do not double post.

jremington: Do not double post.

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