Consider the following scenario:
You have an Aries or Tanjay telephone that is running Lync Phone Edition.
You receive and answer a Public Switched Telephone Network (PSTN) call.
You receive a second PSTN call from a caller that has the same caller ID as the first call.
In this scenario, the first call ends and you are unexpectedly transferred to the second call.
To resolve this issue, install the following security update:
2817465 MS13-054: Description of the security update for Lync 2013: July 9, 2013
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.