You cannot register the handset when the original phone is in use.
Expanding Your Phone
Your phone supports up to 2 handsets (the original handset and the second handset). You can now place a fully featured cordless handset anywhere AC power is available to connect the handset charger. Additionally, you can transfer an outside call to another handset.
•We refer to the TXC580 handset and the
•Before use, you need to charge the battery pack for at least
How to Distinguish the Original Handset and the Second Handset
The original handset and the second handset are identical in appearance. To distinguish the original and the second handset, place the handset in the base charger. If you charge the second handset, HS2 appears, otherwise HS1 appears. There are some restrictions on the second handset, see “Second Handset Operation” on page 44.
Registering the Second Handset
You need to register the second handset before using (for TXC580 only). To register the second handset, simply place the second handset on the original base for at least 5 seconds. The status LED on the original base will flash indicating that registration is occurring. After 5 seconds, the second handset will be registered.