RS-232 Status Feedback Description for the SACD Standard
The SACD Standard reports its operational status by transmitting a block of status data via the RS-232 connector. The block is configured as three 8-bit words. The first and last word always contains hexadecimal code 55 to facilitate message framing and synchronization. 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 SACD Standard 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". SACD Standard 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 SACD Standard
All numeric values described in the following charts are decimal values unless otherwise noted. The description of the three 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 | Reserved | | Reserved | Reserved | | Reserved | Reserved | Reserved | Reserved | Power |
| Bit 7: | Reserved | | | | | | | |
| Bit 6: | Reserved | | | | | | | |
| Bit 5: | Reserved | | | | | | | |
| Bit 4: | Reserved | | | | | | | |
| Bit 3: | Reserved | | | | | | | |
| Bit 2: | Reserved | | | | | | | |
| Bit 1: | Reserved | | | | | | | |
| Bit 0: | Power | 1=Main power is on | | | | | |
6 | Krell SACD Standard Developer’s Reference |
