This 4-wire station family with 12 keys is especially made for camera intercom.
It is possible to connect max.10 camera stations together.
Connector F (connector G for loop thru) is for camera 1-6.
Connector H (connector I for loop thru) is for camera 7-12.
Anyway each camera station can speak with their own cameras or all
camera stations can speak with the same camera.
Each combination is allowed.
For more 4-wire stations with 12 keys see the list on the left-hand side.