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Bridge-IT Codec Keeps Connections Solid and Simple

IP codec’s error correction algorithms and menu of compression choices shine

Sometimes simple is all you need and want. Add in reliable and robust and you’ve stumbled onto the Bridge-IT codec.

Packed in this little blue and white box is everything most broadcasters will ever really need to get audio anywhere. From simple remotes to STLs and studio links, the Bridge-IT uses one Cat-5 to do it all.

Hardware features

The author hoists two Bridge-ITs. The Bridge-IT from codec maker Tieline Technology has a compact design and enables users to rack two units in a 1RU bracket. The chassis is lightweight yet rugged and would easily pack away for a remote.

The rear panel features a rich selection of inputs and outputs.

Input 1 serves as either a mic/line or AES3 input. Input 2 is a balanced XLR line input. There are two XLR line outputs, and a separate AES3 XLR output.

The rear interface also includes 12V DC power, LAN (RJ-45 port), 1/4-inch headphone out, USB, RS-232 serial control and a control port (two opto-isolated/relay outs).

I appreciated the considerable amount of I/O the Bridge-IT provides for such a small footprint. There is no wasted space on the rear, yet there is also enough room to comfortably move cables and access the headphone jack.

My concerns with the rear-panel design are that the 12V power connector is not a twist-lock style connector and that the power supply comprises two separate segments. I generally dislike power supplies that add in another point of failure. It is just too easy to knock a power supply off a desk, or have it fall behind a rack, and with the design of this power supply, one would likely lose power to the device.

The front controls are sleek and easy to navigate. The full hardware control on the panel includes menu navigation buttons and dialing keypad. The buttons are arranged nicely, with convenience shortcuts to home, information, configure and dial/hangup. I appreciated the design of the dialing keypad, with the addition of the *. key to efficiently enter in the IP addresses.

Since this is an IP-only appliance it was obvious that there was much thought put into the way addressing would need to be configured. The front also includes a small LCD display, clean and uncluttered. From the home screen there are only four main menus to choose among. Navigation buttons make these selections in order to drill down to submenus. Users will appreciate that text and button labels are readable without having to be right on top of the box.

Rounding out the front is an SDHC card slot. This is designed for program failover to a recorded file. The Bridge-IT is configured automatically to play out the card’s content in loop mode within 3 seconds when the connection to a remote codec is lost. By placing this slot on the front of the device, it is easy to keep music or promo content current.

I would have liked to see a USB Type A jack on the front as an alternative or addition to the SDHC slot. USB flash drives are so common and universal that I think this addition would be a nice feature.

Software features

Users will be pleased with the inside software offerings of the Bridge-IT.

Beginning with the available algorithms, it comes with Tieline Music, Tieline MusicPlus, G.711, G.722, MPEG Layer II and Linear PCM16 (uncompressed). Enhanced aptX has just been introduced as an optional upgrade. Users can choose to add on AAC-LC and AAC-HE and AAC-HE v2.

The Tieline proprietary algorithms Tieline Music and MusicPlus deliver high-quality low-bit-rate connections for remotes and STLs with minimal delay. While these two algorithms are not compatible with SIP connections or non-Tieline codecs, AAC or MPEG algorithms can be used. In addition to the algorithms, users must select jitter, FEC and delay settings.

As with any IP codec, users need to have a good handle on the abilities of the network to which they are connecting. The choices of algorithm, jitter buffer, FEC (forward error correction) all act together to determine the final output of data and how it is perceived at the remote destination. In the case of jitter buffer, users can choose to use the automatic adaptive buffer or a fixed buffer setting depending on the robustness of the network.

Within the connection configuration menu, users can select various aspects of these options. For those who choose auto adaptive, there is a further priority setting that will attempt to automate the jitter and delay settings as tailored to the connection’s need. Users can program Least Delay, Highest Quality, Best Compromise, Good Quality and Less Delay.

For simplicity in this review, it will suffice to say that users are encouraged to try out each of these settings to best determine what sounds good for their applications.

In testing, I found that in order for the adaptive jitter to perform its best, I needed to have the connection established for a few minutes. This allows the automatic jitter control time to assess the network conditions and negotiate the best conditions. I found that the recommended time of 5 minutes appropriate for ensuring a reliable connection. In my remote studio-to-studio setup between two Bridge-IT codecs, I found the automatic adaptive setting with the selection of Least Delay and Best Compromise to work well, with little to no noticeable delay. I generally appreciated the commonsense approach to achieving optimal settings on the Bridge-IT. I could tell that Tieline’s design was tailored to get this device connected and streaming high-quality audio in a short timeframe.

The next aspect to consider when setting up a connection is forward error correction. Where the jitter buffer acts to smooth out the audio stream (packets) during network congestion, FEC introduces a second stream of packets should those first packets get lost in transmission. The FEC can be applied to either the local or remote locations or both. Within the FEC menu, users can choose from 20 percent, 33 percent, 50 percent and 100 percent values depending on how many packets are getting lost in the IP connection.

I had a robust network for my testing purposes and chose to leave the FEC off. There is no need to enable FEC until the codec actually is showing dropped packets; otherwise you are just using up bandwidth for no benefit.

I recommend walking through Tieline’s setup instructions for connecting to the IP test number. By taking this gradual stepped up approach it is easy to find the sweet spot for the connection. This approach also is helpful for users new to Tieline’s proprietary codecs, Music and MusicPlus.

The Bridge-IT also features a built-in DSP limiter. This intelligent gain control automatically takes care of any instantaneous audio peaks that occur in demanding broadcast situations. The IGC is enabled by default, and it does a nice job rescuing audio that would otherwise be clipped.

Product Capsule Tieline Bridge-IT IP Codec

Thumbs Up
– Music and MusicPlus algorithms (a lot of quality for a little bandwidth)
– Help button (really helpful)
– Web GUI
– Intelligent gain control
– Automatic failover via SDHC slot

Thumbs Down
– Lacking LED with colors for easy visuals on levels
– No headphone jack on the front
– No USB Type A port on front
– No wireless, Wi-Max, 3G
– Twist-lock power cable or strain relief for power cable

Price: $1,395

For information, contact Tieline in Indiana at (317) 845-8000 or visit I tested this feature leaving the IGC recovery set to auto, and the audio reference scale set to G5. The IGC consistently kicked around +20 dBu and nicely handled the hard rock/metal music I threw at it. The IGC auto reset the levels, with no audible detection.

The Bride-IT also provides a Web-GUI for programming via the Web. There is nothing to set up, just enter the Bridge-IT IP address and go. The same menus that are accessible on the unit are available through the Java applet. This feature comes in handy when an engineer chooses to collocate codecs, perhaps in the TOC, and still allow the talent and producers to connect and monitor the codec from the studio. No additional software is needed, and the GUI provides real-time monitoring and configuration.

Last, I tested the automatic failover function of the Bride-IT. I preloaded an SD card with an emergency music MP3 file, and disconnected network connection on my remote device. The failover worked flawlessly and began to play out my file. Once I reconnected the remote codec the programming resumed as normal with the automatic failover going back into standby mode.

The more I tested the Bridge-IT, the more I liked it. In a time when engineering budgets are lean, the Bridge-IT provides quality at a reasonable price.

For simple remotes, IP audio distribution within an LAN or WAN, and STLs the Bridge-IT does not disappoint. With that said, it is important to point out the word simple. Tieline has a whole host of codecs and connectivity products for medium to large remotes, 5.1 surround distribution, multicast applications and other applications.

[Tieline responds: Bridge-IT now has the option of multi-unicast 1 – 6 locations dialed over both private and public networks and multicast 1 to any number of connections over a private network. These licenses plus AAC come standard in the Bridge-IT Pro shipping now. Only the dialing codec needs to have the license installed and any Bridge-IT or Tieline G3 codec can receive a stream.]

The Bridge-IT is not that kind of do-it-all device. However if simple is what you need, you will be more than pleased.