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Digital I/O and Clocking

Optical digital I/O​

iD48 provides two optical inputs and two optical outputs. Each optical pair can be configured for ADAT or S/PDIF in the iD Software Mixer, and the two optical ports can use different formats when required.

  • S/PDIF: 2 channels per optical connection at 44.1, 48, 88.2 or 96 kHz.
  • ADAT: 8 channels per optical connection at 44.1/48 kHz.
  • ADAT SMUX: 4 channels per optical connection at 88.2/96 kHz.
iD48 optical digital inputs and outputs

Word-clock input and output​

iD48 provides BNC word-clock input and output. The word-clock input has switchable 75-ohm termination in the System Panel.

Enable termination when iD48 is the last or only device on a BNC word-clock chain. Do not enable termination at multiple points unless the clocking topology specifically requires it.

iD48 BNC word-clock input and output

Clocking rule​

A digital system should have one master clock. Every other digital device must synchronise to that master through optical digital audio or word clock. Incorrect clocking commonly causes clicks, pops, distortion or failure to lock.

iD48 syncing to an external device via ADAT or S/PDIF​

Connect the external device's optical output to the required iD48 optical input. Set the matching optical format and set iD48's Clock Source to Digital 1 or Digital 2 for the optical port in use.

This allows iD48 to synchronise to the incoming ADAT or S/PDIF optical signal.

iD48 syncing to an external device through optical ADAT or S/PDIF

iD48 as master via ADAT or S/PDIF​

Set iD48's Clock Source to Internal. Connect iD48's optical output to the external device's optical input and configure the external device to synchronise from its optical input. Connect the return optical path as required for audio.

iD48 acting as master clock for an external device through optical ADAT or S/PDIF

iD48 as master via BNC​

Set iD48 to Internal and feed its BNC Word Clock Output to the external devices using 75-ohm BNC cabling. When daisy-chaining with a BNC T-connector, terminate the final device only, according to the requirements of the connected equipment.

iD48 acting as word-clock master for two external devices over BNC

iD48 syncing to an external word-clock master​

Connect the external clock's BNC output to iD48's Word Clock Input using a 75-ohm BNC cable. Set iD48's Clock Source to Word Clock. Enable iD48's 75-ohm termination if it is the last or only device on the word-clock chain.

iD48 synchronising to an external word-clock master over BNC

The diagrams above cover common configurations rather than every possible digital system. See System Panel, Routing and Talkback for digital-format and clock-source controls.

Continue to Rack Installation.