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Adding and registering handsets/headsets
Your telephone can support up to ve DECT 6.0 cordless handsets (AT&T 
model B102-0, sold separately) or up to three cordless handsets and 2 
cordless headsets (sold separately). Visit  
https://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 5). 
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 HS... and ... see manual.
2.  Put the handset you wish to register on the telephone 
base cradle.
3.  The handset shows Registering... and the IN USE light 
on the telephone base turns on. If the registration is 
successful, the handset screen displays Registered and 
beeps. The handset is now registered with the telephone 
base.
If registration fails, the screen shows To register HS... and ... see manual. 
Please start again from Step 1.
Appendix 
For registration, put the handset on the telephone 
base, not the handset charger. 
... see manual
 
ECO
To register HS...
 
ECO
Registering...
 
ECO
Registered
 
ECO