Comrex IP Connectivity Solutions


Comrex has been active in the broadcast arena since the 1960s, and the brand is well known in South Africa for their audio products.

Previously, Comrex audio products and solutions consisted primarily of hybrids, audio connectivity units for ISDN and POTS connections and Studio Call Management Systems.

Today, broadcast technology leans more towards IP-based workflows and technologies. As such, Comrex have evolved their connectivity products, taking advantage of benefits of IP technology by either improving existing products or introducing new ones with additional IP-related features.



LiveShot: The LiveShot is an IP Video Codec and is available in portable and rackmount versions. The units use MPEG-4/h.264 video encoding that accepts Video PAL; SD/HD-SDI on BNC and HDMI connections. Video is sent in both directions including a cue (audio) channel. This is ideal when using the portable unit for live stand-up positions.

The portable unit uses two high performance 3G/LTE modems with high-gain antennas to ensure good mobile connectivity. A USB modem hub can be used to combine up to four USB modems. The portable unit can also take a USB Wi-Fi dongle and on-board Ethernet for fixed network connections.


Access: The Access system is an industry leader for Radio OB activities via 3G/LTE connections. The units can send and receive an audio feed to a rackmount unit. The unit can – using an AAC audio algorithm – change the bitrate of the audio depending on the mobile bandwidth available.

The Access 2USB and newer NX unit are designed for portable OB use – the units can connect via 2 3G/LTE modems, Wi-Fi or Ethernet connections. Both units operate off a rechargeable battery and can accept directly 2 (NX) or 1 (2 USB) microphone inputs. The units also have a bolt-on mini mixer available, so that up to five microphones/audio sources can be mixed. The Access rackmount NX version can also connect via AES67 Audio.

BRIC Link II: The BRIC LINK I/II has, for a long time, been the go-to product for moving audio between broadcast facilities or STL links over IP/internet connections. The codec options on the unit range from High Quality Full Bandwidth Audio/Uncompressed Audio, which is ideal for managed IP networks, to audio compressed as low as 18Kbs to squeeze through unmanaged, problematic networks. The BRIC unit has a host of codecs that can be tailored depending on network conditions and availability. The unit also has the ability to adjust the bitrate automatically depending on network bandwidth conditions.

Opal: The Opal is an IP Audio Gateway allowing out-of-studio guests to interact with the studio via their internet browsers. This product makes operations on the guest’s side very simple: they will be given a URL which directs their web browser to connect with the Opal unit in studio. The Opal uses the OPUS audio encoder, which is built into most web browsers, and the built-in or external microphone on their device.

VH2: The VH2 is a dual VoIP hybrid that interfaces between the telecoms world and baseband audio world into radio studios. The VH2 also offers the same functions as its predecessors: Echo Prevention, Automatic Gain Control and On-Hold functions. The unit also interfaces with a VoIP handset so that calls can be transferred back and forth.

Earshot IFB: The Earshot is a multi-IFB solution utilising VoIP connectivity. For traditional POTS line converted to SIPS protocol, the unit can accommodate 30 SIP callers or 10 Wideband callers. Users in the field can use the FieldTap on a mobile device to interact with the Earshot. The Earshot unit can accept four input feeds which callers can switch between.


Comrex has developed several IP technologies/tools to allow the easy management of connections between their devices.

Traversal Server: The Traversal Server is an online service offered by Comrex so that users have an overview of all the IP devices (video and audio) allocated to their account. The server shows the status of the units – the local IP Address, the connection status, etc. – and is useful for codecs that are used to traverse the internet, as it helps with traversing NATs when connecting between codecs.

Crosslock: Crosslock is built into most of the IP Codecs and allows the ability to bond multiple data connections on a device. The application evaluates which connection is better, based on latency, bandwidth and jitter, and will select the appropriate route. It can also function in a Redundancy mode.

HotSwap: The HotSwap application is built into Access NX and BRIC-Link II devices where Comrex Connect Modems can be used. HotSwap backs up a link (STL or otherwise) with a wireless modem. If the primary Link fails, the units will automatically start using the wireless modem to keep the connectivity between the units seamlessly and revert to the primary once it becomes available again.

For more detailed information, visit the Comrex website or call Telemedia (011 803 3353) to speak to a specialist.