Editing Frame synchronization (section)

== Framing ==
{{Redirect|Flag sequence|the emojis|Emoji flag sequence}}
If the transmission is temporarily interrupted, or a bit slip event occurs, the receiver must re-synchronize.
[[Image:Frame Synced Stream.jpg|frame|none|Frame synchronized PCM stream — telemetry application]]

The transmitter and the receiver must agree ahead of time on which frame [[synchronization in telecommunications|synchronization]] scheme they will use.

Common frame synchronization schemes are:

;Framing bit: A common practice in [[telecommunications]], for example in [[T-carrier]], is to insert, in a dedicated [[Time-division multiplexing|time slot]] within the frame, a noninformation '''framing bit''' that is used for synchronization of the incoming data with the receiver. In a [[bit stream]], framing bits are predictable (do not carry information), and occur at specified positions in the frame.  Correct framing is verified when almost all framing bits  (minus a small allowance for transmission errors) have their predicted values.
;Syncword and flag sequence framing: Rather than a single bit, some systems use a multi-bit [[syncword]] in each frame, or a '''flag sequence''' that marks the beginning and end of each frame. [[High-Level Data Link Control]] and similar systems use flag sequences.<ref>{{Cite IETF |rfc=1662 |title=PPP in HDLC-like Framing |last=Simpson |first=William A. |date=July 1994 |publisher=Internet Engineering Task Force}}</ref>
;CRC-based framing: Some telecommunications hardware uses [[CRC-based framing]], where correct framing is verified when almost all frames have valid CRCs.