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Adding and registering handsets/headsets
Your telephone can support up to 12 DECT 6.0 cordless handsets (AT&T model 
CL80101, sold separately) or up to 10 cordless handsets and 2 cordless 
headsets (sold separately). Visit www.telephones.att.com/headsets 
for a list of compatible DECT 6.0 cordless headsets. Each new handset or 
headset must be registered to the telephone base before use. You must 
register each handset or headset separately.  
To register a cordless headset to this telephone system, please refer to the 
user’s manual of the cordless headset for more details. To register a cordless 
handset, see below.
The handsets provided within your product box are already registered as 
HANDSET 1, and so forth. Additional handsets are assigned numbers in the 
sequential order they are registered (up to HANDSET 12). 
Register a handset to your telephone base
1. Before you begin registration, make sure the handset is out of the telephone 
base or charger and shows To register, see manual.
2. Put the handset you wish to register on the telephone base cradle.
3. The screen shows Registering... Please wait and the IN USE light turns 
on. It takes up to 90 seconds to complete registration. Then, HANDSET 
X Registered appears on the screen, with HANDSET being the handset 
name and X being the handset number (1-12). The handset beeps and  
the IN USE light turns off. The handset is now registered with the 
telephone base.  
If registration fails, the system will automatically try to register again. If 
registration fails after the third try, Registration failed appears on the screen 
for a few seconds, and then To register, see manual. This may take up to five 
minutes to occur. Please start again from Step 1.
For registration, put the handset on the 
telephone base, not the handset charger. 
Appendix