Your question about Siemens Optiset E analogue adaptor

Lets you connect any standard analogue device such as fax, modem, fax/modem, full-duplex seakerphone, analogue phone, or wireless phone to your optiset E phone and use the optiset E phone and analogue device simultaneously.

• Supported on basic, advance, advance plus, advance conference and memory telephones
• The analogue line and optiset E operate simultaneously with unique extension numbers
• minimizes or eliminates need for analogue line card
• TIA/EIA 464 compatible  Connector type(s): One R-J11.