Exchange 2007 – UM – Terminology

For the telephony challenged Exchange 2007 professional…  Below are some common concepts and terminology that may stumble across during your Unified Messaging deployment.

Telephony Concepts
Terminology	Description
Circuit Switching (Telephone Networks)	→ Network in which there is a dedicated connection. → Analog and digital circuit switched networks        ▪ Analog - deisgned for voice transmission        ▪ Analog transmission signal must be encoded or converted into a digital format         before it enters the telephony WAN
Connectivity Concepts	-->T1 and E1 lines      ▪ E1 line can handle more simultaneous calls      ▪ T1 is used mostly in North America and Japan Trunk and tie lines       ▪ Trunk line - connects corporate PBX back to the phone company's PBX system       ▪ Tie line - typically a T1 or E1 line used to connect two or more corporate PBX systems Time Division Multiplexing (TDM)     ▪ Transmits separate voice signals simultaneously over a single physical, high bandwidth phone line
Packet Switching (Data Networks)
Voice over IP (VoIP)	Voice over IP (VoIP) is a technology that contains hardware and software that enabled people to use an IP-based network as a transmission medium for telephone calls. Protocols: SIP ; RTP ; T.38 (fax)
Session Initiated Protocol (SIP) and Real-Time Transport Protocol (RTP)	SIP  Only used for setting up and tearing down voice or video calls RTP:  All voice and video communications occur over RTP
Common Existing Enterprise Scenarios
System	Description
Central Office Telephone Exchange (Centrex)	A business phone service offered by a local telephone company from the phone company's central office (CO)
Key Telephone System	Is a multiple line telephone system typically employed by small organizations.
Private Branch eXchange (PBX)	aka Telephone switch or telephone switching device… Connects office telephones in a business to the public telephone network.
PBX Types
Type	Description
Analog PBX	Voice and signaling remain analog
Digital PBX	A code converts audio to a digital signal of a particualar format and vice versa.  Digitized voice is routed over circuit-switched channels
IP PBX	The IP phone is a node on the data network and can digitize voice ; Voice traffic will be packet switched and routed over LAN and WAN data networks.
Hybrid PBX	A combination of IP and digital capbilities in a singe PBX
PBX Concepts
Concept/Term	Relationship to Unified Messaging
Direct Inward Dialing (DID)	Only requires DID for targeted custom auto attendants, such as one to go to "Sales".
Dial Plan	Dial plan +extension is unique identifier
Coverage Path	Used on specific extensions to route calls from the PBX to Unified Messaging
Hunt group	Direct calls to VoIP gateway and/or Unified Messaging
Pilot number	Used for Call answering, Outlook Voice Access, and Auto Attendants. (Address or Label Group)
Unsupervised Transfer	Transfer method used by Unified Messaging
VoIP Gateways
Concept
Their function-----	Translate TDM or Telephone circuit switched based protocols from PBX system to protocols based on VoIP or IP   (SIP; RTP ; T.38)
Types of VoIP Gateways	IP/PBX  - Single device capable of communicating directly with Unified Messaging server using supported VoIP protocols.
	PBX (legacy) and IP/VoIP gateways - Two separate components are deployed ; the legacy PBX and the VoIP gateway performing translation to supported VoIP protocols