Table 255
+===========-===========================================================+
| ADR code | Description |
|-----------+-----------------------------------------------------------|
| 0h | Sub-channel Q mode information not supplied |
| 1h | Sub-channel Q encodes current position data |
| | (i.e. track, index, absolute address, relative address) |
| 2h | Sub-channel Q encodes media catalogue number |
| 3h | Sub-channel Q encodes ISRC |
| 4h - Fh | Reserved |
+=======================================================================+