This 3.5mm TRRS CTIA Smartphone Connection Cable is used to connect the 3.5mm headphone port of an iOS or Android smartphone to the mobile phone port of a 55 or 300 Series conference phone.
The 4.9' cable is wired for CTIA standard used by most smartphones. It is terminated with a 3.5mm TRRS male connector at one end and an RJ12 6/6 DEC connector at the other.