Inbound Routing

Calls destined for an analog device from a Lync endpoint are sent straight to the gateway specified on the contact object. In this case the Lync user experience is that the call looks like it was placed to a PSTN number. The trickier part is how calls from a caller outside of Lync Server 2013 will reach the analog device. The call flow resembles the following sequence and is depicted in Figure 17.15:

1. The PSTN or PBX caller dials the analog device DID.

2. The call is routed through the media gateway and to Lync Server.

3. Lync determines that the DID belongs to an analog device.

4. Lync places a new, outbound call to the analog device with the calling party set to the PSTN or PBX phone number.

5. The call is routed to the media gateway associated with the analog device.

6. Gateway configuration associates the destination number with a specific analog port, and rings the device.

Figure 17.15. Inbound call to an analog device.

The takeaway here is that there are really two legs to this call. The first is between the PSTN or PBX caller and the Lync Server, and the second is between the Lync Server and the analog device.