PSTN Gateway and IP PBX Interoperability
For IP-based real-time applications that must communicate with a PSTN network on one side and a unified communications network on the other side, Microsoft Unified Communications Managed API (UCMA) 3.0 provides an application the ability to interoperate with SIP PSTN gateways and IP-PBXs with the unified communications network.
The following SIP peers can connect to the UCMA application.
SIP gateways.
SIP-enabled IP-PBXs that support the following phones.
SIP phones
Soft phones that support SIP
SIP peers should support the following protocols.
SIP—RFC 3261
DTMF—RFC4733
SDP—RFC 3264
In addition, SIP peers:
Must provide media session parameter negotiation (endpoint, codec, and, if applicable, encryption parameters) through SDP, as defined in the SIP and related RFCs and used in SIP.
Must provide media/audio transport using RTP/RTCP over UDP.
Must meet the Supported IP Gateways requirements listed in Telephony Advisor for Exchange 2010.
The following illustration shows a typical setup.
For more information, see Trusted Domains and SIP Gateways.