A bit array that contains the value of the front panel LEDs and the annunciator. This is a packed bit string; each LED is encoded into 4 bits (a nibble). The first nibble is stored in the high order bits of the first octet. The second nibble is stored in the low order bits the first octet, etc. However, the current mapping is that the first three nibbles are reserved, the fourth nibble has the value of the 'annunciator', and the 'normal' LEDs start with the fifth nibble. If the LED values are not available, a zero length string is returned. The following shows the meaning of each bit (bit 0 is the least significant bit) when it has a value of one: bit meaning 0 green light 1 yellow light 2 blinking 3 reserved