Blackmagicdesign ATEM Live Installation And Operation Manual page 2262

struct tally
uint8
bit 0: monitor device program tally status (0=off, 1=on)
bit 1: monitor device preview tally status (0=off, 1=on)
bit 2-3: reserved (0b00)
bit 4-7: protocol version (0b0000)
uint8[0]
bit 0: slave device 1 program tally status (0=off, 1=on)
bit 1: slave device 1 device preview tally status (0=off, 1=on)
bit 2-3: reserved (0b00)
bit 4: slave device 2 program tally status (0=off, 1=on)
bit 5: slave device 2 preview tally status (0=off, 1=on)
bit 6-7: reserved (0b00)
uint8[1]
bit 0: slave device 3 program tally status (0=off, 1=on)
bit 1: slave device 3 device preview tally status (0=off, 1=on)
bit 2-3: reserved (0b00)
bit 4: slave device 4 program tally status (0=off, 1=on)
bit 5: slave device 4 preview tally status (0=off, 1=on)
bit 6-7: reserved (0b00)
. . .
Master Device
Byte 7 MSB 6
Version Version
0
(0b0) (0b0)
Reserved Reserved
1
(0b0) (0b0)
Reserved Reserved
2
(0b0) (0b0)
3 ...
Slave Device
(1)
Slave Device
(2)
Slave Device
(3)
5 4 3
Version Version Reserved
(0b0) (0b0) (0b0)
Slave 1 Slave 1 Reserved
Preview Program (0b0)
Slave 3 Slave 3 Reserved
Preview Program (0b0)
Monitor Device
2 1 0 LSB
Reserved Monitor Monitor
(0b0) Preview Program
Reserved Slave 0 Slave 0
(0b0) Preview Program
Reserved Slave 2 Slave 2
(0b0) Preview Program
Developer Information 2262