When you sign in to a common area telephone that is running Microsoft Lync Phone Edition, only the last digit of your telephone number extension is displayed on the telephone.
Resolution
To resolve this issue, install the following cumulative update:
2937310 August 2014 Cumulative Update 5.0.8308.738 for Lync Server 2013 (Front End Server and Edge Server)
Note After you apply this cumulative update, you must run the Update-CsAddressBook cmdlet in the Lync Server 2013 environment.
