AUDIO STREAMS | 37
9 Audio Streams
The main job of the Z/IP ONE is to make high quality audio connections with other units in remote locations, usually over
the Internet. Moving audio through the Internet is not always simple, but the Z/IP ONE includes tools to help make it
easier. To that end, your Z/IP ONE supports three different types of connections.
9.1 Telos Session Control Protocol (TSCP)
The primary method that the Z/IP ONE uses to connect to other Zephyr/IP codecs is called Telos Session Control
Protocol, or TSCP. The primary features of this protocol are:
♦ Server authentication (optional):
¸ Directory service
¸ Presence service
¸ NAT traversal
¸ Media relay
♦ Bidirectional audio transfer
♦ Agile Connection Technology (on applicable codecs)
TSCP is a connection protocol. It sets up the connection between two Zephyr/IPs, but does not transport the audio. For
that, RTP (Real-time Transport Protocol) is used. TSCP is the method used by two Zephyr/IPs to discover where they
should each send their RTP streams.
The ZIP Server
TSCP connections can be made with or without the assistance of a directory server. They are point-to-point connections
that transfer audio in both directions. Like all the Z/IP ONE’s connection modes, TSCP allows you to use different codecs
and bit rates in each direction.
A server is configured and maintained by Telos Systems as a service to our Zephyr/IP customers. It provides a set of tools
to enhance the functionality of your Z/IP ONE: a directory, presence service, NAT traversal, and a media relay service.
Directory Service
The directory service allows your Z/IP ONE to register itself in a group, with a unique device name. The group and device
name together form a persistent “phone number” for your Z/IP. Other users can always find and call your Z/IP ONE
regardless of what IP address you happen to be using that day. This is especially important when your ISP has given you a
dynamic IP address, or when you take your Z/IP ONE on the road.
The directory service also allows you to locate other Zephyr/IPs by browsing the server directory right from your
Z/IP ONE. Wildcard and Soundex (phonetic) searches allow you to find the device you’re interested in even if you
don’t remember the exact spelling of the other device’s name or group.
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