A320 Family, PDL Adapter Unit

Data loading commonality, flexibility, and security for your legacy A320 fleet.

A Modern and Affordable Replacement to Unsupported Airbus Multi-Disk Drive Units (MDDU)

Spectralux is pleased to offer a modern and secure replacement of the unsupported Airbus Multi-Disk Drive Unit (MDDU) to A320 series operators. The MDDU is an on-board data loader used for uploading software and downloading data from Line Replaceable Units (LRUs) on Airbus aircraft. Operations using the MDDU require physical 3.5” floppy disk media. These diskettes have become obsolete, are unreliable, have limited data capacity, and no security. For these reasons, Spectralux recommends and offers a replacement Portable Data Loader (PDL) adapter to allow standard ARINC 615 PDLs to be used for loading LRU software.

Product Overview

This package replaces the onboard MDDU in the center pedestal panel with the Spectralux PDL adapter. The PDL adapter connects standard ARINC 615 PDLs via a 53-pin connector for onboard software data loading to the aircraft LRUs. This modification removes the MDDU and replaces it with a Spectralux PDL adapter. The PDL adapter connects directly to the existing MDDU connector on the aircraft and occupies the same location and form factor as the original MDDU. Since the PDL adapter is a direct replacement of the MDDU, the aircraft Data Loading Routing Box (DLRB) and Data Loading Selector (DLS) equipment maintain their intended functions.


Airbus has validated various solid-state PDLs with internal mass storage capabilities for loading software on newer A320 planes equipped with Centralized Data Loading Connector (CDLC). These solid-state PDLs are able to manage various types of media other than diskettes through the use of a USB Port (e.g. CD-ROM, USB Stick, PCMCIA, CF). Modern solid-state PDLs feature network connectivity and enhanced data security. Many software manufacturers are meeting new guidelines for digital signatures and the validation of software. With network connectivity, airlines can manage and distribute software parts to the aircraft without the physical movement of media disks.

Aircraft Integration

The PDL adapter assembly consists of a wire harness and connectors attached to a metal enclosure. The wires and connectors used are of Airbus standards. Wiring provisions for the PDL adapter are based on Airbus SB 34-1411. The form factor of the PDL adapter assembly conforms precisely with that of the existing Sagem MDDU. The PDL adapter maintains interfaces with the Data Loading Routing Box (DLRB) and Data Loading Selector (DLS). The DLRB is a multi-routing device consisting of ARINC 429 inputs and outputs to the connected LRUs for loading software. The DLRB routes input and output data between the PDL adapter (previously the MDDU) and the target LRU. The DLS allows maintenance personnel to control the DLRB activity and operation mode. It shows available LRUs on the DLS display and allows the selection of the desired LRU to be loaded.


Form, Fit, and Function replacement of existing MDDU



  • Provides an affordable interface to secure ARINC 615 PDL devices
  • Removes unsupported, unreliable, and limited capacity disk drives
  • Allows data loading commonality between old and new A320s


  • Direct replacement to existing MDDU (Form, Fit, and Function)
  • Reuse existing MDDU aircraft wiring with CFDIU Pin Programming Change

Product Package

  • Spectralux PDL Adapter unit
  • Installation and certification support documents, based on FAA STC

For more information, please contact your Spectralux sales representative or:

Kim Collins