What is call appearance and line appearance in IP phones?

[Christopher Chan]

Detlef Lechner wrote:
> Hello,
> 
> Synaptic: "Twinkle is a voice over Internet Protocol (VoIP) SIP Phone: A 
> softphone for making telephone calls using SIP over an IP network. 
> Twinkle supports direct IP phone to IP phone communication or a network 
> using a SIP proxy to route your calls. Twinkle provides making basic 
> voice calls, and in addition the following features (regardless of the 
> services that your VoIP service provider might offer): two call 
> appearances (lines), ..."
> What is a »call appearance«?  I have found a description but I still 
> don't understand what a call appearance is: 


Two call appearances just means that you can handle two internal phone 
lines in the phone system. One of them can be tied to a direct number 
from an outside line and the other will be your internal extension. Or 
however the phone system is setup. One could be your extension and the 
other tied to your voicemail.