User manual

Installation Imagestore 750 User Manual
Page 278 Miranda Technologies Inc.
GPIO/LTC
Imagestore 750 with Dolby options has additional RS485 serial ports on the
rear, which are dedicated to Dolby metadata. Dolby Metadata is transmitted
on a serial RS485 link as an intermittent and asynchronous serial data stream,
bursts of data occur at the video frame rate.
The RS485 ports are accommodated in a 44-way GPIO connector.
This connector contains a variety of signals:
• General Purpose Interface port
o 16 General Purpose Interface ports, software configurable
as inputs or outputs
o 1 GP_+12V supply (500mA max)
o 1 GP_+5V supply (500mA max)
o 1 GP_GND ground pin for GPI interface
• Linear Time Code port (LTC+, LTC-, LTC_GND)
• Total DC Fail Alarm
o 2 pin “contact closure” for Total DC voltage failure
condition within the Imagestore 750 unit
o Otherwise, when unit is normally powered, these 2 pins are
isolated.
o May be used to switch on some external warning
buzzer/lamp (provided this is less than 400mA, and less
than 25V)
• Dolby Metadata RS485 serial ports
o 4 ports, 4 differential signals