Remote TSP is not tested/supported for use with the Cisco TSP

RTSP introduces some significant configuration requirements into a TSP installation, as well as a number of different application/network and API layers, into which Cisco has little to no visibility. While RTSP theoretically works 'as is' with existing TSPs, in practice there can be interactions and issues, which require a commitment to testing/debugging/development, and - importantly - coordinated support infrastructure and partnership with Microsoft to debug field issues.

Particularly, the support burden is potentially large, as Cisco (and partners) could be involved in troubleshooting TSP issues involving RTSP with greatly expanded complexity and dependencies (compared to stand alone TSP installations), the majority of which technology Cisco wouldn't have control or visibility into (i.e. how can Cisco tell if the issue is with RTSP, RTSP configuration, the network, or the Cisco TSP itself..?) Also Microsoft's commitment to RTSP is minimal: they were not addressing outstanding issues do not plan on doing any more work on RTSP.

As a result of these considerations, and the fact that demand for support of RTSP was very low (and that other architecture worked just as well in most circumstances) the decision was made not to commit resources to testing and supporting RTSP going forward.

Our company developed CTI Softphone which does not require any installation on client and work fine in RDP.
We are opening all TAPI lines on server side.
B.R.
Vladimir