So you have Lync, and every time you want to look up an extension of someone in your office you are left with nothing. Why, Why is this, why doesn’t things just work. As frustrating as this may be it happens for a reason.

Lync expects all the phone numbers in Active Directory to be in the E.164 format. In short they should be something such as this:  +1-111-5550000 etc… If they are not like this, you will need to normalize them if you want Lync to public them.

Normalization Rules
Normalization rules define how phone numbers expressed in various formats are to be routed for the named location. The same number string may be interpreted and translated differently depending on the locale from which it is dialed. Normalization rules are necessary for call routing because users can, and do, use various formats when entering phone numbers in their Contacts lists.

Method used to fix this
I utilized the contact card functionality of Lync and a series of regular expressions found around the web and came up with a Company_Phone_Number_Normalization_rules.txt located in the Lync share 1-webservices-1abfiles followed by a quick “Update-CsAddressbook” all you need to do is give some time for the address book to regenerate.

I give a big thanks to the guys / gals over at Network Administration Secrets for this one.