Telos Zephyr iPort MPEG Gateway

click to enlarge

Welcome to the iPort:

The Telos iPort houses eight stereo MPEG codecs in a single 2RU box, capable of either 8 bi-directional or 16 encode-only channels. It can be used for any application where MPEG encoding and/or decoding is needed for transmission over IP channels such as VPNs, satellite links, Ethernet radio systems, and Telco or ISP-provided QoS-controlled IP services. Applications include studio-to-transmitter links, network distribution systems, and links to remote studios. With an appropriate server, the iPort can be used for Internet streaming, broadcasting to mobile phones, and audio distribution systems.

The iPort uses the Livewire standard. A single Ethernet cable is all that's needed for all inputs and outputs plus remote control. If you aren't using Livewire yet, just pair the Telos iPort with an Axia AES/EBU or Analog Audio node to make a standalone high-density audio codec package.

It uses state-of-the-art MPEG codec technology to conserve network bandwidth, while preserving high audio quality. A range of codec types and bitrates are supported. They're all licensed from Fraunhofer IIS, the inventor of MP3 and co-inventor of AAC. They are the highest-possible quality implementations, running on a powerful Intel floating-point processor.

Uncompressed audio is transferred via an Ethernet connection to/from your Livewire network, eliminating expensive, space-consuming converters and connectors. A second Ethernet connector interfaces the compressed audio to a WAN.

Configuration and monitoring is via Web, with the front-panel LCD offering immediate local display of status and basic parameters, such as the assigned IP number.

Available Codecs:

- AAC-HE Stereo
- AAC-HEv2 Stereo
- AAC-LD Mono
- Layer 3 (MP3)

Link Operating Mode:

In the link operating mode, the iPort is intended to be used over IP connections that have reasonably good Quality of Service, with controlled packet loss, jitter, and bandwidth. The AAC codec has a concealment mechanism to deal with occasional packet loss, but it is not intended for conditions where packet loss is routine such as on the public Internet. There are configurable buffers to accommodate jitter, but longer buffer lengths add to delay. When you need to use non-QoS-controlled links, the Telos Z/IP family of products are a perfect solution because they offer adaptive mechanisms to deal with network problems.

Streaming Mode:

When used with an appropriate server, the iPort can be used as a simple, reliable encoder for Internet or internal audio distribution. Because the iPort generates standards-based MPEG streams, a wide variety of PC-hosted and hardware players can be used for listening. The iPort is an encoder that can generate multiple output streams. However, to feed a large number of listeners, a server is required. SHOUTcast (yes, that is the way it is spelled), Steamcast, or other SHOUTcast protocol compatible servers are commonly used for this application. For delivering audio over a LAN or private network, the encoder and server can be together in the same rack. For public streaming over the Internet, the encoder typically runs in the place where the audio is generated (e.g. a studio) and the server is in a place where a lot of bandwidth is available such as an Internet co-location site.

Streams that are served by SHOUTcast protocol servers can be heard on Winamp, Apple iTunes, XMMS, VLC, Foobar, MS Windows Media Player, and many other PC software players. Many hardware players are also on the market, such as Logitech's Slim Player and Freecom’s network player.

The diagram shows a simple set-up. A Livewire node provides live audio input, which connects directly to the Livewire Ethernet jack on the iPort. The iPort’s WAN jack goes to a LAN that connects to a link that leads to a remotely located server, which provides streams to listeners over the Internet. Many variants are possible. For example, a Livewire PC driver could provide the source audio rather than a hardware node. (However, there must be a hardware node somewhere on the network to provide the timing clock.) An installation which already has Livewire equipment would not need a node dedicated to the iPort - you would just select the channels you want to stream directly from the Livewire network.

The original idea for the SHOUTcast server was to accept an audio input from the Winamp player, which has a special "DSP" plug-in. However, since Nullsoft (the company that designed both Winamp and SHOUTcast) published the specifications for the interface, it was established that encoders like the iPort can connect as well.

If you are planning to make public broadcasts via the Internet and you don’t want the hassle of running your own server, or don’t have enough network bandwidth, you can host your broadcast through a third party that will handle the streaming for you. You can search the Internet for the streaming host solution that fits your needs. The SHOUTcast forums would be a good place to start.

The installation would be like the one in the diagram. In this case, one LAN ties together the node, iPort and an Omnia dynamics processor. Another network links to the WAN (presumably with a firewall in the picture). This offers good security since the LW network is isolated from the WAN. It would also be possible to use a single network on the studio side. In this case, the firewall would be responsible for protecting the LW network.

The Omnia 8x is a perfect companion to the iPort. You get 8 channels of high-quality dynamics processing at low cost, and with the same simple one-RJ-45 connection advantage that the iPort offers.


The iPort is an innovative approach to providing MPEG codec functionality by using Livewire for its audio interface. Its features include:

- High density, 8x8 bi-directional or 16 encode-only channels in a 2U box.
- Low cost. We’ve built the iPort on a single industrial motherboard, rather than the usual multiple DSP cards in a frame approach. Together with the Livewire-only audio interface, the iPort costs a fraction of legacy card-frame designs.
- Direct livewire connectivity. For people who already have facilities based on Livewire IP audio, there is no need for any interface or conversion. The iPort simply plugs into a port on the Ethernet switch and all encode/decode channels are connected with 24-bit/48kHz quality.
- Web-based configuration from anywhere on the network.
- Full range of state-of-the-art MPEG codecs. AAC-LD for delay-sensitive applications, AAC-HE and AAC-HEv2 for low bitrate requirements. Standard AAC for best quality and resilience to packet loss at higher bitrates.
- Excellent quality and high-density streaming encoder with the advantage of the Livewire IP Audio network interface.

- Zephyr iPort MPEG Gateway
- Zephyr iPort MPEG Gateway with Time Zone Delay

- aptX Enhanced Audio Codec