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Lyra Presence and Busy Lamp Field (BLF)

The 2talk Cloud PBX supports Presence and Busy Lamp Field (BLF)

Presence indicates the current availability status of a user, showing whether they are available, on a call, away, busy, or offline

BLF (Busy Lamp Field) is a visual indicator on a desk phone or operator console that displays the presence status of monitored extensions in real time

Together, presence and BLF allow users and operators to see at a glance who is available before transferring a call or attempting to contact a colleague

Lyra supports presence state subscription, event type "presence", that is commonly used by soft clients. However, currently presence state notification is only supported between user agents that send PUBLISH requests to the server with state updates. Effectively user agents configured for presence, and that send PUBLISH requests, can monitor each other but not other devices configured for the "dialog" event type.

Lyra supports BLF subscription, event type "dialog", that is commonly used on IP phones


How presence works

  1. User's device registers with the platform and establishes a presence subscription
  2. Platform tracks the user's current state based on call activity & manual status changes
  3. When the user's state changes, the platform sends a SIP NOTIFY message to all devices subscribed to that user's presence
  4. Subscribed devices update their display to reflect the new state
  5. Other users and operators can see the updated status in real time

How BLF works

  1. A BLF key on a desk phone is programmed to monitor a specific extension
  2. Phone sends a SIP SUBSCRIBE request to the platform for that extension
  3. The platform acknowledges the subscription and sends the current state
  4. BLF key reflects the current state via its indicator light
  5. When the monitored extension's state changes, the presence server sends a SIP NOTIFY to the monitoring phone
  6. BLF key updates to reflect the new state

Portal Settings

Enable Presence/BLF on this line only? When enabled, presence and BLF monitoring is active for this line only. Other lines or devices associated with the same user will not reflect presence or BLF status changes.

Enable presence/BLF for queue login status on this line only: When enabled, the BLF indicator shows only whether the user is logged in or out of the queue. It will not reflect other activity such as calls in progress or ringing. Use this setting when queue availability is the only status that needs to be monitored on this line.

Enable Presence/BLF for DND status on this line only: By default, BLF is unaffected by Do Not Disturb (DND). To reflect DND status on BLF enable this setting. When enabled, DND must be set using star codes only — the portal DND setting should not be used.