Where are the secrets in the doom-comm mission?

[TheHon]

Hi Creston or anybody else

 

I would like to know where the 3 secrets in this level are (the communication stuff)

I found only the one through a grate near the beginning.

Is this also a secret if you open the door with the r5-unit. It didn't count in my game.

 

Any help would be great to complete the level with all secrets.

 

Thanks