Krell Industries RC-5, RS-232 manual Word 1 Start of Message, Word 2 General Status

RS-232 Status Feedback Description for the Home Theater Standard 7.1

The Home Theater Standard 7.1 reports its operational status by trans- mitting a block of status data via the RS-232 connector. The block is configured as eighteen 8-bit words. The first and last word always con- tains hexadecimal code 55 to facilitate message framing and synchro- nization. When the data block is sent through an RS-232 port, each

8-bit word transmitted will also have 1 stop bit associated with it. The exact RS-232 protocol settings for both status and Home Theater Standard 7.1 control are as follows:

9600 Baud 8 Data Bits 1 Stop Bit No Parity

The feedback system is available only through the RS-232 connector. The status can be activated in two ways. The first is to ask for status to be sent by sending the RS-232 command code "STAZ". The second is to enable auto status by sending the RS-232 command code "ASTEZ". Once the auto status command is sent, the Home Theater Standard 7.1 will transmit a status block whenever the status changes. Auto status is disabled by sending the RS-232 command code "ASTDZ". Auto status remains enabled until AC power is removed or turned off. When AC power is reapplied, auto status is disabled.

RS-232 Status Block Descriptions for the Home Theater Standard 7.1

All numeric values described in the following charts are decimal values unless otherwise noted. The description of the eighteen 8-bit words follow.

The values marked Reserved must be ignored during pattern matching.

Word 1: Start of Message

Bit	7		6	5	4	3	2	1	0
Description	0		1	0	1	0	1	0	1
	Bit 7 – 0:	Hexadecimal 55

Word 2: General Status I

Bit

7

6

5

4

3

2

1

0

Description

System Mute

User Mute

Zone 2 Mute

Current Zone

Input Trigger

Zone 2 Only

Zone 2 Power

Main Power

Bit 7:

System Mute

1

= Internal mute is active

Bit 3:

Input Trigger

1

= 12V input trigger is active

Bit 6:

Main Mute

1

= Main mute is active

Bit 2:

Zone 2

Only

1

= Only Zone 2 power is on

Bit 5: Zone 2 Mute

1

= Zone 2 mute is active

Bit 1:

Zone 2

Power

1

= Zone 2 power is on

Bit 4:

Current Zone

1

= Zone 2 is active

Bit 0:

Main Power

1

= Main power is on

Krell Home Theater Standard 7.1 Developer’s Reference 11