Most later model Sony camera control units have a DB-25 connector on the rear of the CCU that allows the user to patch in directly to a Clear-Com Pro PL or Encore PL 2-wire unbalanced intercom system.  This is an acceptable practice for one or two CCUs, but it is recommended for multiple CCUs wired back into a 2-wire party-line system that the user take the 4-wire CCU audio feeds and route them into a Clear-Com 4-wire to 2-wire interface such as the IF4W4 which supports up to four 4-wire to 2-wire conversions or the EF-701M which supports a single 4-wire to 2-wire conversion.  The pinouts for the Sony CCU into a 2-wire PL line are shown below:






















Sony CCUs that use this common 2-wire configuration:
CCU-550
CCU-590/790
CCU-TX50
HXCU-100
HDCU-900/950
HDCU-1000/1500
HDCU-2000/2500
A 4-wire / 2-wire connection diagram is attached below as a PDF.