Aastra 6731I - Incomplete Configuration; No Service

12 Model 6731i IP Phone Installation Guide
Installation and Setup
Connecting a Handset
Turn the phone over and locate the handset jack marked j. Insert one
end of handset cord into the jack until it clicks into place. Then route the
handset cord through the groove as shown in the illustration below. Attach
the handset to the other end of the handset cord.
To Handset