TRENDnet TVP- 221H, VoIP Gateway manual How the TVP-221H Operates, Atpm, Destination

Chapter 3	3
TVP-221H Telephony

Concepts

The TVP-221H enables the transmission of voice and fax traffic over any IP network by digitizing voice and fax signals, encapsulating the information within IP packets, and then sending the packets across the IP network

3.1How the TVP-221H Operates

1.The TIM inside the TVP-221H digitizes analog voice signals at 8 Kbps.

2.TVP-221H system software handles the:

•Capture of telephone number presented as DTMF tones.

•Mapping the telephone number to the IP address of remote VoIP Gateway.

•Setting up calls with remote TVP-221Hs utilizing H.323 call control protocol.

•Digitizing, compressing and encapsulating the voice into IP packets and transmission of the IP packets onto the Ethernet LAN.

3.A router attached to the LAN forwards the IP packets across the WAN, where they will be received by another VoIP Gateway at the remote.

4.The process is reversed at the remote VoIP Gateway.

3.2ATPM

To allow you to easily dial a telephone or fax on the network, the TVP-221H maps a series of dialed digits to the IP address of the remote TVP-221H whose phone or fax you are calling. This mapping information is contained in a database inside each TVP-221H called the dial plan.

Based on the dial plan, the Address Translation and Parsing Manager (ATPM) inside the TVP-221H maps telephony numbers to IP addresses of remote VoIP Gateways. The ATPM collects telephone number dialed by users, decides whether the dial string is part of the dial plan and, if it is, maps it to a remote TVP-221H / TVP-224HR. When the call is set up to the destination, a sub-string of the original dial string will be sent along to the remote VoIP Gateway.

3.3Destination

The destination is where a call is terminated. Typically, for inbound calls from the IP network, the TVP-221H terminals the call at one of the telephony ports. The

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