[Icom] ICOM 2100H Programming Information?

[Ekki Plicht]

> I have been burning the midnight oil trying to determine 
> how the checksum is calculated for the channel data 
> transmitted to/from the icom 2100H. Has  anyone cracked 
> this already? I know what all of the other content is 
> and this  is between  me and writting my own programming 
> SW. 

> ~~nnd0720200000000000000000000000000000000000000000000000
> 000000000000000000B9}
> ~~nnd0740200000000000000000000000000000000000000000000000
> 00000000000000000099}
> ~~nnd0760200000000000000000000000000000000000000000000000
> 00000000000000000079}

The preamble bytes are not included in the checksum.
So, start adding bytes from 07 on until the last byte before the checksum.
(All bytes as hex):

07 20 20 
00 00 00 00 
00 00 00 00 
00 00 00 00 
00 00 00 00 
00 00 00 00 
00 00 00 00 
00 00 00 00 
00 00 00 00 
B9

07 + 20 + 20 = 47 (zeros ignored)
negate result (one's complement)
!47 = FF FF FF FF B9
the lower 8 bit are the checksum

07 + 40 + 20 = 67 (zeros ignored)
negate result (one's complement)
!67 = FF FF FF FF 99
the lower 8 bit are the checksum

07 + 60 + 20 = 87 (zeros ignored)
negate result (one's complement)
!87 = FF FF FF FF 79
the lower 8 bit are the checksum


73d,
Ekki, DF4OR