> 4.2.3 | Control Field

> The control field contains control information to define the frame.

> Table 5: | Coding of the control field

> Frame Type | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8
> SABM (set asynchronous balanced mode) | 1 | 1 | 1 | 1 | P/F | 1 | 0 | 0
> UA (unnumbered acknowledgement) | 1 | 1 | 0 | 0 | P/F | 1 | 1 | 0
> DM (disconnected mode) | 1 | 1 | 1 | 1 | P/F | 0 | 0 | 0
> DISC (disconnect) | 1 | 1 | 0 | 0 | P/F | 0 | 1 | 0
> UIH (unnumbered information with header check) | 1 | 1 | 1 | 1 | P/F | 1 | 1 | 1

> P/F: Poll/Final bit
> Commands: P = 1, Responses: F = 1
> For each DLCI, only one frame with P = 1 may ever be expected.