This Cable Works With Avaya Desk Phones And May Work With Additional Manufacturers Check With Our Compatibility Guide For More Information. Use This Electronic Hookswitch For Remote Call Answering And Call End. This Permits The User To Place Or Receive A Call Without The Need To Lift The Handset. This Control Is Entirely Electronic And Eliminates The Need For A Mechanical Handset Lifter Device. For Use With The Plantronics Cs Series Wireless Headsets (Cs500 And Savi 700).