Blue Flower

DDL Products

SIU v.2.3

Source Interface Unit


SIU is a Detector Data Link (DDL) Source Interface Unit designed for use in the data acquisition (DAQ) system of the ALICE experiment.

However, it is a standard interface and can be used in any DAQ-s.

It transmits data from front-end electronics to a DDL readout card through a high-speed optical link.


  • 2.125 Gb/s optical data transmission
  • Complies with CERN proprietary Detector Data Link (DDL)
  • 206 MB/s maximum sustained bandwidth
  • Half duplex 32-bit data path and flow control
  • Radiation tolerant (tested on the ALICE radiation levels)

DDL Features

  • Instant-on, (automatic link synchronization and management)
  • Supports remote control and firmware upgrades of the Front-end system
  • Bit error rate << 10-12, very high error detection rate, CRC check on data blocks
  • Standby support


  • Half Common Mezzanine Card (CMC) form factor
  • User replaceable Small Form Factor Pluggable (SFP) optical transceivers
  • Duplex LC optical connector
  • LVTTL interface, single 3.3V supply voltage
  • Compatible with: RORCv3, RORCv2