It depends on what ports the phones are listening and what information cab be retrieved there.
For example, if the phones display a web-page on port 80 and that page contains any useful information such as model or serial number, this information can be extracted with the feature called Remote XML. It can be used to retrieve the page and parse it with regular expressions.
Here is a screenshot of this feature. If you are not sure how to write a regular expression to extract information, please send me a copy of the page (HTML) that the phones respond with: