transfer databits s5 <---> S7

i try to figure out a construction at work !
when they transfer databits from S5 to a S7 DB93 DB2.2 becomes DB125.dbx1.8 !
ther must be a good explanation why it's not dbx2.2 but i can't figure out why ?

I cannot see exactly why S5 D2.2 becomes S7 DBX1.8

DBX1.8 should be impossible, as the permissible bit range is 0 .. 7.

The way S5 and S7 adresses are handled is not the same.
In S5 they are arranged in words.
In s7 they are arranged in bytes.

Quote from Hans Berger:
S5 data D[.0 .. 7] becomes S7 data DBX[(2n+1).0 .. 7]
S5 data D[.8 .. 15] becomes S7 data DBX[(2n).0 .. 7]

This explains that the bit positions in a word are swapped bytewise, when adressing S5 and S7.
But it does not explain your adress DBX1.8.
Also, the S7 word adress should be the double of the S5 word adress.
Following the rules from Hans Berger S5 D2.2 should convert into S7 DBX5.2 .

How do you transmit the data from S5 to S7 ?

maybe i just used bad example ! i will check if it's this conversion tomorrow !
thanks !