Remote Call Control

Remote Call Control was the original form of Lync Server PBX integration introduced with Live Communications Server 2005. It enables users to control their legacy desk phone from Lync. Users can click to dial a contact in their buddy list, which actually instructs the desk phone to place the call. It also allows for their presence to be automatically updated to “In a call” when they are using the legacy phone. In this case the media stream and codec negotiation is not handled by Lync Server at all. Instead, Figure 17.9 displays how the traditional desk phone and integrated PBX handles the call.

Figure 17.9. Remote Call Control with a CSTA gateway.

A Computer Supported Telecommunications Applications (CSTA) Gateway was always required to translate the SIP call signaling between Lync Server and the integrated PBX. These gateways were generally a PBX appliance or an additional server component from the PBX vendor that added complexity and required additional.

Lync Server 2010 added support for the “Get” and “Put” verbs over SIP to control presence, which can negate the need for a CSTA gateway, but many PBXs don’t support this feature.

Remote Call Control does not provide users any Enterprise Voice features for controlling calls, assigning delegates, or configuring call forwarding settings. It also does not work remotely, so a user must be on the corporate network, which limits its usefulness for remote workers. Remote Call Control is considered an inferior option and organizations should avoid new deployments of this scenario.