Sennheiser UI 765 Instruction Manual page 7

Connections
A
B
A Headset
B Dictaphone Jack 3.5 mm
C Handset
D Phone
E Aux/PC
C
Box connection
RJ11
"Color Black"
RJ11
RJ11
RJ11
D
Peripheral devices
Secom Quick disconnect
Jack 3.5 mm
"Color Black"
RJ11
Depending on phone
Jack (2x) 3.5 mm/USB
E
3