Bit-oriented.-whereas cops are based on characters, bit-oriented protocols (bop) are based on bits and the position of the bits. the most widely used bops in the industry are ibms sdlc and hdlc. architecturally, bop differs from cop in that it uses positional significance of the bits, not control characters. for example, in cop, a soh is required after syn is transmitted. soh informs the receiver that a header is following soon after. in bop, after the 8 synchronizing bits have been transmitted, the receiver knows that the next set of bits to follow is the header information.