Any character can use a walkie-talkie, smartphone, tablet, etc. to communicate with other characters as well as access the Intergalactic Bank (IGB), Holonet News, and SliceWare websites built for In-Game use. Additionally, information regarding Alien, Droid, and Human species as well as historical events pre-15BBY from the Wookiepedia may be used In-Game.
Restricted radio channels for Faction Contacts can be used only by players currently playing a character belonging to that Faction. Eavesdropping on these channels is cheating. All the other channels are open for you to use and switch between as you like.
If you need to reach your Faction Contact, don't go to Mission Control, use your radio instead and stay In-Game. The MCs will keep radios in Mission Control to monitor and answer incoming communications. If there is no answer right away, please be patient and keep trying.