I have some questions regarding the UC520 and its voice features and configuration.  First, I have the UC520 updated to the latest firmware release.  Now that it is current, does it include the same features as the UC540/560 when it comes to configuring the device?  Am I able to access features on the UC520 via the GUI interface that I would be able to access on a 540/560?

Also, we are moving over to a SIP phone system in the near future.  We will also be utilizing DID lines for incoming calls and for fax.  With this configuration, will all the current call features available on the 520 be there?   For example, will we still be able to transfer calls via extension or since we are using DID will we lose the ability to use extensions?  Is there a document out there that shows the differences/similarities between using DID as opposed to other configurations?

How many call paths are supported in a SIP configuration?

Thank you.