1 set up one signaler for each frequency, click on another signaler with one in hand, to copy the frequency from the one in your hand
  to the one you are clicking on
2 then click on a voice analyser and say your keyword, and attach it to a signaler (you can do this multiple times to have different keywords, and they dont have to be set to a different frequency
  attach it by using a screwdriver on both the signaler and the voice analyser
3 then set up a radio with a custom frequency, have one set to "speaker" and place it in a room with your voice analyser/signaler,
  and keep one set to mic with you, or set your headset to the custom frequency, but you wont hear the common channel anymore
4 attach the signaler copies to the doors you want them to lock/open (open will only work on doors that dont need ID's) and say your
  keyword
5 DO THIS AFTER YOU ARE SURE YOU HAVE THE RIGHT SIGNALER IN THE DOOR: attach iron to your maintenance hatches by using the screwdriver on the door then using a stack of iron on it
if you think you will do this more than once, make a txt. document like this one and type in something like this:
127.7-17 "cargo lobby doors"
127.7-18 "cargo shuttle doors"
127.7-19 "cargo mining bay doors"
127.7-20 "cargo exterior doors"