B737 DEU EEC

[TyRod]

Hi guys,

Need some inputs on this:

"Loss of either DEU results in a loss of signal to both EECs. The EEC ALTN lights illuminate and each EEC reverts to the alternate mode to prevent the engines from operating on a single source of data."

I was convinced that the DEUs was receiving signals from the EECs and then were responsible for displaying the datas on the DUs.

What am I missing here?

Also, can somebody tell me why a hard alternate mode have been installed.
Was keeping the EEC in soft not good enough? (even with the possible exceedances)

In alternate mode, is the Thrust levers controlling directly the HMU?

Thanks

Thanks