DIRECTV Set-Top Box Information for the Installer
DIRECTV, Inc.
March 5, 2008
Version 2.2
Page 14 of 42
DTV-MD-0058
Start
Reset Command
Parser
(Parser is free)
*Command
Prefix (0xFA)?
Send
STB Response
= NACK_PREFIX
NO
**Command Parser
attaches to current
data port
(Parser is in use)
*Known
Command?
Send
STB Response
= NACK_CMD
YES
NO
*2 Byte
Command?
Read 2
nd
Byte of a 2
Byte Command
*Known
Command?
Send
STB Response
= ACK_CMD
YES
NO
YES
YES
NO
A
A
Send
STB Response
= ACK_RESET
Send
STB Response
= DATA_ERROR
Send
STB Response
= CMDBUF_OVFL
Input
Parameters?
*Correct # of
Input
Parameters?
Send
STB Response
= NACK_PARAMS
Send
STB Response
= ACK_PARAMS
Execute Command
and send Return
Data Stream as
appropriate
(Parser is Busy)
Command
completed
successfully ?
Send
STB Response
= NACK_FCNOK
Send
STB Response
= ACK_FCNOK
(Parser is not busy)
YES
YES
NO
NO
YES
NO
Figure 4-1. Service Command Parser Flowchart