Allen-Bradley 1779-KFMR User Manual page 78

Continuing with the example, consider a node receiving the following bit
stream from across the link:
0101 11110 1001
The previously inserted zeros would be deleted as follows:
Zeros Deleted
0
0101 1111 1001
The original bit stream would then be passed through as follows:
0101 1111 1001
Invalid Frame
A node must ignore any invalid frames it receives. A frame is invalid if it
falls into either of the two following categories:
A frame is invalid if it is not properly bounded by two flags. An
aborted frame falls into this category.
A frame is invalid if it is too short. A valid frame requires a minimum
of 32 bits between flags.
Order of Bit Transmission
The order of transmission of bits within a frame depends on the field the
bits are in.
In the address field, the order of bit transmission is low bit first. An
address of 1 would be:
Time
1 0 0 0 0 0 0 0
Chapter 6
HDLC Data Link Layer
1011 11101 11110 1011
0 0
1011 111 1 1111 1011
1011 1111 1111 1011
11100
0
111 0
1110
6 9