The Nortel Networks i2004 NTDU82 is the first in a line of the i2004, Internet Protocol, desktop telephone. It's features include hand-free mode, speaker and voicemail. The LCD screen is monochromatic with soft buttons that are user programmable. To identify your model of the Nortel Networks phone, read the label located on the underside of the telephone. A distinguishing feature between models is the silver bezel around the screen. The NTDU82 does not have a silver bezel. The i2002 and i2004 model support the exact same features, but the size of the display and the number of keys differs.
Diagnose issues you have with your Nortel Networks i2004 IP Telephone with the Troubleshooting Guide