HD9084 HDTV Caption Encoder Manual
SERIAL CONTROL PROTOCOL Page 4-1
4. CONTROL-A SERIAL PROTOCOL
The following sections describe the control protocol used by the HD9084 closed caption encoder. It is
often referred to as the “Control-A Protocol” because most commands begin with a control-A character.
The control-A character is abbreviated as ^A. Section 4.1 provides a quick reference table to the
command set. Sections 4.2 to 4.6 provide a full description of the commands with examples.
4.1. COMMAND QUICK REFERENCE
Control-A Command Quick Reference
Controlling the Caption Decoder
Block Upstream XDS Packet
Show Port Permission Maps
Alter Port Permission Maps
Table 4-1: Control-A Command Quick Reference