CS50 DISCONTINUED , AS WELL AS HOOKSWITCH
Yes!
A Hook Switch is used to answer/end calls remotely without the use of a handset lifter on some Funkwerk phone models.
Plantronics uses the Plantronics CS50 Electronic Hookswitch for Siemens Phones
Works on Funkwerk models:
CS290U
CS410
CS410U
IP-S400
THERE IS NO LEITNER SENNHEISER HOOKSWITCH FOR FUNKWERK PHONES