Look what I found (check towards the bottom under installation challenges):
GN Netcom GN 1000 RHL Remote Handset Lifter 01-0369 design is based on a comprehensive study of telephone measurement specifications, so it works with over 90% of all business telephones*. Unless your phone has a truly unusual design, it will work with yours. And since the GN 1000 RHL has been tested to lift and lower the heaviest handsets 100,000 times, you know it will keep working for a long time.
Features:
Automatically lifts and lowers handset
Works with most standard phones
Magnetic sensor technology
Fast operation
Easy to install and use
Online indicator
Elegant design, near-zero footprint
Benefits
Answers and ends calls remotely.
Eliminates compatibility questions.
Reliable operation.
Never miss a call.
Gets you up and running quickly and easily
Lets others know when you’re on a call.
Doesn’t add to desktop clutter.
* Currently not compatible with:
Lucent Magix 4424+
Siemens Optiset
Nortel i2004 VolP phones
Installation challenges:
Avaya Index
Alcatel Reflex, Advanced and Premium models
Nortel Norstar T7100, T7208, T7316
Nortel Meridian M3900 series telephones