When a phone does not have a communication channel established with any SIP proxy and a call is in progress; the phone displays the Limited Phone Service message. The message disappears automatically, or the user can cancel it. An icon indicating Acquiring Service is displayed on the top line of the phone. This icon does not go away until a communication channel is established with a SIP proxy. The icon is an exclamation mark within a triangle similar to the following:

If there is no ongoing call and there is no communication channel between the phone and the proxy, then the phone displays the message Acquiring Service.

When a failover occurs, and a call is preserved, the call appearance line of the phone displays the following preserved call Indicator: