TDS400 has a modular design using an universal Europe card rack. It includes:

- An input card with the line balancing amplifiers and a leveller to automatically adjust the levels between the different sources or the different soundtracks.

- Four cards including Linswick-Riley filters; 24dB per octave giving a very low crosstalk between each band and a perfect  phase recombination. The block diagram has been designed for changing only one card to alter one cut-off frequency. Each card has:

•  A noise gate with adjustable threshold.
•  A compressor with adjustable ratio, threshold, attack time and release time.
•  A limiter with adjustable threshold.
•  An adjustment of the frequency band gain allowing , after processing, to create your own radio sound and also to re-adjust the very compressed signals.
•  A led display on the front panel showing the action and the reduction of compressor's gain, the action of noise gate and the activation of limiter.
•  A jumper gives the option of linking the left and right channels at the command processing level or leaving them independents.

- An output card with line balancing amplifiers and a general limiter with adjustable threshold on the general mixing.

- A supply card that includes a Vu-meter and a headphone amplifier to control the output level.

- A settings card (optional) enabling the calibration of the TDS 400.  This card can be inserted into the  front panel after the  open, after the closure of the front panel, these settings are inaccessible for security reasons.

The TDS400 has a remote controlled Bypass, allowing, for example, on network on the same audio path to process a local program and not reprocess a national program.  Also a station that subscribes to a program bank can only process the local program. In the Bypass position the output limiter is still active.