This guide will help you replace the handset in your Nortel Networks i2004 IP telephone. You may need to replace your handset if the microphone or speaker in the handset is not working.
Turn phone over to view the back.
Disconnect the handset cord from the back of the telephone by squeezing the clip and pulling striaght out.
Disconnect the telephone cord from the handset the same way as the previous step.
Connect the new handset by squeezing the clip attached to the phone cord and sliding the cord into the bottom slot of the phone.