key refers to your Primary Directory Number, also known as an extension number, or line key. You can use this key to make a call. You can press this key, then dial; or you can predial, then press this key to actually send the digits.
The Primary Directory Number key also provides automatic redialing. By pressing the key two consecutive times after picking up the handset, or choosing the handsfree dial option, the telephone set automatically redials the last number dialed.
Return to the M2008, Basic Telephone Set
Return to the M2616, High End Telephone Set