NEC RS-232C manual Direct TV Chanel Read & Write, Direct TV Chanel Read & Reply

14. Direct TV Chanel Read & Write

When DTV unit (Option unit) is installed, channel settingｓ is read and write directly.

14.1 Direct TV Chanel Read & Reply

1) The controller requests the monitor to read channel information.

Header		Message	Check code	Delimiter
SOH-'0'-Monitor ID-'0'-'A'-'0'-'6'		STX-'C'-'2'-'2'-'C'-ETX	BCC	CR
Header
SOH (01h): Start Of Header
'0' (30h): Reserved
Monitor ID: Specify the Monitor ID which you want to get Model Name.
Ex.) If Monitor ID is '1', specify 'A'.
'0' (30h): Message sender is the controller.
'A' (41h): Message type is "Command".
'0'-'6'(30h, 36h): Message length
Message
STX (02h): Start of Message	32h, 43h): Direct TV Channel Read command
'C'-'2'-'2'-'C' (43h, 32h,
ETX (03h): End of Message
Check code
BCC: Block Check Code

Refer to the section 4.5 “Check code” for a BCC calculation.

Delimiter

CR (0Dh): End of packet

2) The monitor replies the result to the controller.

Header	Message	Check code	Delimiter
SOH-'0'-'0'-Monitor ID-'B'-'1'-'2'	STX-'C'-'3'-'2'-'C'-MajorCH-MinorCH-ETX	BCC	CR

Header

SOH (01h): Start of Header

'0' (30h): Reserved

'0' (30h): Message receiver is the controller.

Monitor ID: Indicate a replying Monitor ID.

Ex.) When this byte is set to 'A', the replying Monitor ID is '1'.

'B' (42h): Message type is "Command reply".

'1'-'2'(31h, 32h): Message length = 18bytes

Message

STX (02h): Start of Message

'C'-'3'-'2'-'C' (43h, 33h, 32h, 43h): Direct TV Channel read reply command

MajorCH: Major Channel (00000000h – FFFFFFFFh), '0'-'0'-'0'-'0'-'0'-'0'-'0'-'0' ～ 'F'-'F'-'F'-'F'-'F'-'F'-'F'-'F'

MinorCH: Minor Channel (0000h – FFFFh), '0'-'0'-'0'-'0' ～ 'F'-'F'-'F'-'F'

ETX (03h): End of Message

Check code

BCC: Block Check Code

Refer to the section 4.5 “Check code” for a BCC calculation.

Delimiter

CR (0Dh): End of packet

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