OFf-hook and On-Hook

The terms on-hook and off-hook are telephony terms for a key concept used in Jabra call control. Namely, the terms describe the call state of a device, and their value can be true or false (1 or 0 respectively).

When initiating a call, the call state of the device is set to active (off-hook is true), when ending a call, the call state of the device is set to inactive (off-hook is false).

This terminology is based on early telephony, where you physically lifted the telephone receiver off the hook to make a call and put it back on the hook when the call ended.

Your application (in essence, a softphone) gives you greater flexibility than analog telephones. For example, with analog telephones you could have multiple active lines at the same time. On the other hand, with your application you can choose the call recipient from a list, before activating the line to make the call. Previously, you had to activate the line before dialing numbers.

On the other hand, with your application you can choose the call recipient from a list, before activating the line to make the call. Previously, you had to activate the line before dialing numbers.

The interaction metaphor of the hook-switch lets Jabra devices work with your application as well as traditional desk phones using the same protocol.