Partyline: How do interface a Hitachi CU-HD500 camera control interface to a MS-704 main station?

Question:  I'm attempting to connect a Hitachi CU-HD500 camera control unit to an existing MS-704 main station on our party-line system.  Is this CCU compatible with a Clear-Com 2-wire connection or with a 4-wire connection as a secondary connection with an EF-701M interface?
Answer:  Yes, the Hitachi CU-HD500 camera control unit should interface into both 2-wire unbalanced party-line Clear-Com or RTS intercom systems and can also interface into Matrix 4-wire balanced audio IC systems.  The DB-25 connector on the rear panel of the CCU marked "communications"  contains the pin outs for either connection mode.  The interior of the CCU also has five dip switches that need to be configured for either 2-wire or 4-wire IC connections. 
Using the charts below the user should be able to interface into either mode.
 For two wire mode, set all the dip switch settings 2 wire and clear-com. Then take pin 3 of the partyline from the main station and connect to Pin 5 and loop to pin 7 on the DB25. Do not connect pin 2 from the party line mainstation. Connect the shield pin 1 from the party line mainstation to pin 6 on the db 25.
  If need be the CCU can be setup in 4-wire mode and interfaced into a party-line 2-wire system by using an EF-701M interface or IF4W4 interface depending on how many channels of communications are needed on the CCU (the CCU has 2 channels available, they are labeled Production and ENG). 
Hitachi DB-25 pin outs for 2-wire and 4-wire IC connections



















Hitachi CU-HD500 internal dip switches for IC configuration