The unit operates on the push-to-talk principle. There are spring-loaded switches on the front panel which the tender
depresses in order to talk to the divers or to enable one diver to talk with the other diver(s). When none of these
switches are depressed, the tender hears all three diver channels. If the tender desires to speak to all the divers
simultaneously, he depresses and holds the PRESS TO TALK ALL DIVERS switch. If the tender desires to speak to any
one diver individually, he depresses and holds the appropriate PRESS TO TALK switch; i.e., DIVER 1 switch to speak to
diver one. DIVER 2 switch to speak to diver two, and DIVER 3 switch to speak to diver three.
Figure 2-14. Divers Intercommunication Set.