OffHook For Linux - OffHook allows work groups on the same local network to monitor the phone.

OffHook allows work groups on the same local network to monitor the phone status of other OffHook users. With the click of a mouse, a user can communicate to other users that they are beginning a phone call. When the call is over, they can easily switch their status back to available. Although designed for telephony, you could use OffHook to track any kind of on/off state. (Lunch, meetings, out-of-the-office, etc.)