I. INTRODUCTION
The Comrex BRIC-Link II is a low-cost, high-performance soluon for audio-to-IP conversion. Leveraging many of the
core technical aspects of Comrex’s successful remote broadcast ACCESS product line, the BRIC-Link II provides for
an elegant way of moving Linear or compressed audio with very low delay. BRIC-Link II may be used over a range
of IP links, is very simple to use, and doesn’t require the expense of more full-featured codecs. While it carries an
entry-level cost, BRIC-Link II maintains superb audio specificaons and hardware reliability, making the system
suitable for STLs and other mission-crical funcons.
BRIC-Link II is contained in a small desktop package. Two BRIC-Link IIs may be installed to occupy 1U of rack space.
APPLICATIONS
The BRIC-Link II is uniquely suited to point-to-point “nailed up” high-quality audio links over a variety of data
networks, like ISM band IP radios, T1s, satellite channels, WANs, and LANs. The robustness of the BRIC Normal
technology (Broadcast Reliable Internet Codec) used in the box allows the system to perform well on the public
Internet as well (using AAC or Opus compression modes).
AUDIO CODING
For users concerned about delay and coding arfacts, the BRIC-Link II offers a robust stereo or mono Linear mode
that does not compress audio. In addion, unique to real-me audio codecs, BRIC-Link II offers FLAC lossless
compression, reducing network throughput by 30-40% with absolutely transparent coding and no tandem coding
concerns. For situaons where further reduced bandwidth is desired, BRIC-Link II offers AAC/HE-AAC modes as
standard, allowing superb audio quality at dramacally reduced data rates. For compability with mobile phone
and web applicaons, BRIC-Link II also implements Opus audio compression, along with VoIP standard G.722.
TRANSMISSION MODES AND DELAY
The BRIC-Link II is a true codec, offering a full-duplex stereo encoder and decoder in each unit. When two-way
transmission is not required, the reverse channel may be disabled. The BRIC Normal technology incorporated
includes a jier buffer manager that automacally balances delay and stability, dynamically increasing and
decreasing delay based on network performance. For networks where QoS is known, these parameters may be set
to maintain a consistent level of jier buffer.
End-to-end coding delay in Linear modes is less than 25 ms. Delays when using FLAC and Opus modes are less than
30 ms. AAC modes incorporate around 100 ms total end-to-end delay while HE-AAC modes deliver around 220 ms.
In addion to coding delay, network propagaon and jier buffers will add delay to any IP link and are network
dependent.
