Cisco IP CONFERENCE STATION 7936 Administration Manual page 109

Chapter 4 Troubleshooting the Cisco IP Conference Station 7936
Problem Description
LCD screen display issues
DTMF delay
OL-4746-01
Resolution
You might see beat frequencies (scan lines) in the
LCD screen if you are using certain types of older
fluorescent lights in your building. Moving the
IP Conference Station away from the lights, or
replacing the lights, should resolve the problem.
When you are on a call that requires keypad input,
if you press the keys too quickly, some of them
might not be recognized.
Cisco IP Conference Station 7936 Administration Guide
Other Troubleshooting Information
4-5