Dolby Laboratories S01/13621 - Manual (Page 39)

Dolby Installation Guidelines Serial Communications
6-3
Table 6-4 Pin Connections for RS-485 Ports (Excluding Metadata Outputs)
Pin Connection Comment
1 Shield (chassis ground)
2 TX A Asynchronous data out –
3 RX B Asynchronous data in +
4 Ground
5 NC
6 Ground
7 TX B Asynchronous data out +
8 RX A Asynchronous data in –
9 Shield (chassis ground)
• DP570 Metadata output
• DP572 Metadata output
Table 6-5 Pin Connections for Metadata Output Ports
Pin Connection Comment
1 Shield (chassis ground)
2 RX A Asynchronous data in –
3 TX B Asynchronous data out +
4 Ground
5 NC
6 Ground
7 RX B Asynchronous data in +
8 TX A Asynchronous data out –
9 Shield (chassis ground)
6.3 Metadata Connections
Metadata is data that relates to audio data. It is carried in both Dolby E and Dolby
Digital bitstreams.
The dialogue level is given here as an example of a metadata parameter. The dialogue
level (dialnorm) value represents the average level of the audio. It is referenced to a
level of digital full scale. It represents this average level even in a program that has no
dialogue. As part of the Dolby Digital decoding process, the average level of the
audio will be reduced to –31 dBFS. If the dialogue level was set as –27 dBFS, then a
4 dB reduction will be applied. This can be used to ensure that the decoded audio is
kept at the same level, and that a listener does not have to “gain ride” every time they
change channels.