From Paterva Wiki
Phone number notation is really hard to define as everyone has their own way of using it. In Maltego phone numbers are broken up into 4 different parts. These are: Country code City code Area code Rest (last 4 digits) Parsing of numbers happens in reverse - the last 4 digits of a number is first chopped from the end. The next 3 digits are used for area code, another 3 for city and the remainder is used for the country code. If the number you are using as input does not fit this format don't panic - the transforms re-arrange the numbers in various forms when searching for it. As with a person entity, this entity has additional fields that allows for more focussed searhcing - see properties. When the last 4 digits are ommited in the search Maltego will use these are wildcards - this is useful for obvious reasons...
List of country dialing codes on Wikipedia
See also (other entities)
Properties of this entity in Maltego
(URLs) Collected URLs when used with search engine transforms - note that these are only populated after the transform has executed
(Country dial code)
(Last four digits)
(Additional search terms) This field is used to focus the search. When looking for a telephone number where you only have the last 7 digits and not populating this field Maltego will certainly provide you with useless information. But - if you know that the phone number belongs to a software engineer you should add an additional search term of 'software engineer' - this will add the term to every search and will focus your results.
(Additional country short code)) This field limits the query to results in a specific country (or TLD). The ISO 3166 country codes can be found at wikipedia. When used in conjunction with the additional search term you can ensure that you will be looking in the right place.