Linksys CIT310 - Manual (Page 12)

Dual Mode Cordless Phone for Yahoo! Messenger with Voice
6 Chapter 2: Get to Know the Dual-Mode Cordless Phone
The Handset Side Panel
The Handset Side Panel
If you have a headset (optional), open the headset flap. Then plug a 2.5 mm headset into it to use this option.
Headset
flap
Figure 2-5: Handset
side panel