5.2 Firmware
The ADI-648's main part has been realized using  programmable logic. By exchanging a little component called EPROM, both function and behaviour of the unit can be changed at any time.

At the time of writing this manual, the unit is shipped with firmware 2.5. This firmware is not compatible to older units, which do not have the REMOTE key. The firmware version is displayed after power on by the AUDIO LEDs for about one second.

Since firmware version 2.5 not only ADAT input 8, but also the current Matrix configuration influences the output mode. If MADI output group 8 is assigned to any input, the device generates 64 channel format. This is also true when MATRIX STATE is set to OFF. As this channel assignment is factory default, all ADI-648 with  firmware 2.5 will generate 64 channel mode as default mode. To activate the 56 channel format for the MADI output, the MADI output group 8 has to be set to Mute, and no signal must be present at ADAT input 8.