If step 4 checks good, do EPC step 5.
One at a time, connect and check each audio accessory at its appropriate control box. Set the control
box MONITOR switch to INT ONLY, and turn VOLUME control to full volume (maximum).
e. EPC step 5. This step checks audio accessory keying.
(1) Check step 5a as follows:
(2) If step 5a checks good, do step 5b as follows:
(Set the key switch to the center position before going on.)
(3) If step 5b checks good, step 6 would be checked.
f. EPC step 6. This step checks the shutdown of the intercom set. Check step 6 as follows: