BACnet PTP

A

Thread Starter

Andrew Chiang

Hi All:

Can anyone tell me what is the standard used for CRC (Cyclic Redundancy Check) in BACnet PTP protocol ? My assumption is CRC-16. Is it correct?

Andrew ST Chiang
 
No. Annex G of the spec lays it all out for you. PTP specifies an 8 bit CRC on the header and a different, 16 bit CRC-CCITT on any data. The polynomials are G(X) = X to the eighth + X to the seventh + 1 for the header and G(X) = X to the sixteenth + X to the twelth + X to the fifth + 1 for any data.

Best,
B.O. Jan. 4, 2002
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Robert Old
System Architecture
Siemens Building Technologies, Inc.
 
K
According to my copy of the standard, the header CRC uses one octet and the polynomial X8+X7+1, and the data CRC uses 2 octets and the CRC-CCITT polynomial X16+X12+X5+1.

--
Ken Irving
 
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