ACCESS - IP / Internet Digital Audio Codec

ACCESS Portable at stadium

The industry-standard ACCESS from Comrex is a true revolution in audio codecs. Developed from the ground up for use over the public internet, it provides 2-way, stable, stereo, low-delay audio over pretty much any type of internet connection, including wireless systems such as WiFi, 4G and 3G. A pair of rackmounts will provide a superb ISDN replacement whilst the portable unit effectively gives you a radio car in the palm of your hand! It literally is as good as it sounds and is being used by a huge number of broadcasters worldwide.

ACCESS is the first codec to use BRIC (Broadcast Reliable Internet Codec) technology to deliver wideband audio over the public internet and other IP networks in real time. It includes AAC algorithms from Fraunhofer IIS - such as the remarkable AAC-ELD - which provide near-transparent audio transmission. There is also a built-in linear uncompressed mode and FLAC lossless audio coding, suitable for managed networks with a high Quality of Service. Because the ACCESS constantly adapts to changing network conditions, audio delay is kept to a minimum whilst maintaining audio stability.

ACCESS Rackmount

ACCESS is just as happy running 2-way 15kHz mono over a standard phone line (POTS) and is compatible in this mode with the Matrix and Vector.

The ACCESS rackmount is a 1U unit with analogue stereo audio inputs and outputs plus digital AES on XLRs. There are also serial and GPI ports which can be sent alongside the audio to the connected unit. A standard phone line connection and Contact Closure completes the rear panel.

ACCESS web interface

The front panel contains only level indicators and a status LED. All setup and connection functions, as well as detailed status, audio levels and network statistics are accessed through the user-friendly web interface. Operation is as simple as selecting a remote unit from the 'address book' and clicking Connect, while advanced configuration menus are available for power users who wish to configure all aspects of the audio coding process.

Apart from normal point-to-point connectivity, ACCESS also supports multi-streaming, IP multicast and SHOUTcast™ connections. In addition, the HotSwitch application provides "live" audio switching between a number of remote codecs, all connected simultaneously to the studio and receiving either program audio, talkback or clean feed.

The ACCESS Portable is the perfect complement to the Rackmount and provides the same technology in a handheld, battery-powered unit not much bigger than a PDA. The Portable includes two USB sockets for use with WiFi adapters and 3G/4G cellular 'dongles', making it easy to get an IP connection from a wide range of locations. With current UK mobile data tariffs, you can use the ACCESS over 3G for just £1 per day!

ACCESS and BGAN satellite terminal
ACCESS and BGAN Satellite Terminal

The algorithm best suited to the network available can be selected from either the Rackmount web GUI or the built-in touch screen on the Portable. Audio meters are displayed on the Portable's screen and a web browser is included to allow easy connection to WiFi hotspots where a password or credit card number is required. An optional 5-channel mixer is also available, turning the ACCESS Portable into a fully-integrated remote audio solution.

For use in the most remote locations, the ACCESS units will even work seamlessly with a satellite terminal to provide the same high-quality audio expected of the BRIC and AAC algorithms from almost anywhere in the world using the Inmarsat BGAN (Broadband Global Area Network) service. For more information please contact us.

ACCESS Portable rear ACCESS Portable with mixer


N/ACIP SIP / EBU-3326 Codec Compatibility

The N/ACIP international committee was set up by the European Broadcasting Union to hammer out a common protocol to interconnect codec brands and resulted in EBU Tech 3326, a technical document describing how best to achieve this goal. It defines several encoding algorithms plus the transport layer and incorporates the SIP protocol that determines the handshake that takes place at the start of an IP codec call. ACCESS and BRIC-Link codecs already include SIP compatibility which also has the advantage of making them compatible with other non-broadcast products such as VoIP hardware, software and mobile phone apps such as CSipSimple for Android phones and Media5-fone for iOS. ACCESS and BRIC-Link do not fully comply with EBU3326 as they do not feature MPEG Layer-II but apart from this, they have been tested to be compatible with several other manufacturers' devices using encoders supported by both products. In general, when connecting between Comrex hardware, it is best to use one of the proprietary modes which take advantage of other algorithms and special features such as BRUTE (UDP Reliability and Congestion Avoidance).

BRIC-TS - Traversal Server

The BRIC-TS Traversal Server is hard to describe but an extremely useful development as it enables connections to be made between BRIC-enabled devices, such as ACCESS and BRIC-Link codecs, quickly and simply.

A codec connected to a local network will usually be 'hidden' from the outside world behind an IP firewall or router, which makes accepting incoming calls from an external unit troublesome without some re-configuration of the network. However, by first making a connection to the BRIC-TS Traversal Server, a codec can "punch a hole" through the firewall, providing a return path by which other codecs can connect in. The Traversal Server keeps a record of the route by which data needs to travel to reach each registered codec, allowing users to call another device by "name" rather than by "number" (or IP address). The audio does not pass through the server - only the IP addressing is handled by it. Imagine being able to call into a portable that is on a 3G network or a codec that is connected to the internet at a WiFi Hotspot!

To take advantage of the BRIC-TS Traversal Server, you will need to buy a licence for each ACCESS Codec you wish to register. This is a one-time cost and the licence code is entered into each codec via the normal user interface. You get an account of your own on the BRIC-TS Server where you can see the status of each codec (idle, connected etc), its software revision and other useful information. On each codec's screen, you see a list of all other units by name and whether they are available, allowing connections to be made instantly without having to enter any details manually.

Optional Road / Flight Cases


AX-ROAD-EX – For ACCESS Portable and Accessories

Olive Green waterproof Explorer case made from high impact poly-ethylene and rugged enough for even the most severe and hazardous environments, fitted with high-density foam to take the ACCESS Portable, 1 battery and 1 spare, mains power supply, USB WiFi adapter, POTS modem and 4G / 3G dongle, with ancillary cables and manual held in the lid by Velcro straps.

Overall dimensions are 360 x 305 x 195mm approx (W x D x H) and the weight is 2.75kg (empty) or approximately 8.5kg with equipment. There are two snap-shut catches to close the lid and the moulding incorporates provision for a padlock.


AX-ROAD-MX – For ACCESS Portable With Its Mixer and Accessories

Silver-grey Comrex high impact ridged plastic case with aluminium frame and sturdy fasteners, rugged enough for the cargo hold of an aeroplane. Custom foam for the ACCESS (also available for the Vector/Envoy, Matrix or Hotline/Nexus) accommodates the ACCESS Portable with 1 battery and 1 spare, USB WiFi adapter, POTS modem and 4G / 3G dongle, mains power supply, cables and headphones etc. A pre-cut area of foam can be easily removed to accommodate the AX-MIX add-on mixer. With the cover closed, there is space for manual and other items between the foam.

Overall dimensions are 495 x 395 x 215 mm approx (W x D x H) and the weight is 12.5kg (empty) or approximately 18.5kg with equipment. There are two wind-down catches to close the lid and provision for a padlock.

Data Packages – Unlocked 4G / 3G Dongles and Paid-up Data Bundles


For the ACCESS to connect via 4G / 3G (UMTS), a suitable plug-in USB modem 'dongle' needs to be used. We have a lot of experience with mobile connectivity and are happy to share this information with customers.

In most situations, it is possible to choose a data network that will provide suitable performance in a particular geographical area but it can be very convenient to be able to use a different network from time to time. This is particularly important when roaming, where data charges can be extremely high, and when away from base where another network may provide better coverage.

Comrex Connect Modem

Comrex Connect Professional Grade Modem

Comrex Connect has arrived and comes in both LiveShot and Access configurations. Connect is a pro-grade, high performance cellular data modem that ensures the highest degree of broadcast reliable data transmission. Each devices comes in a ruggedised, industrial case with a carrier-certified, high gain antenna (2.1dBi) and sturdy, customised mounting hardware for either the LiveShot or Access Portable codecs.

The ACCESS runs under Linux and whilst most USB dongles will have Windows drivers available, Linux support is less certain. We therefore stock unlocked modems that we know work reliably with the ACCESS and provide high quality connectivity.

We are also able to provide paid-up data packages (for example a year's data connectivity on a specific network) and other data contracts in conjunction with our modems (depending on network / geographical location). We have a good deal of experience in using various networks around the world so please contact us if you have any specific requirements.

If you wish to use an existing 4G or 3G modem with the ACCESS, you may find it useful to consult Comrex's list of supported devices. While many other devices will work, these have been verified and are therefore recommended: Compatible 3G/4G devices for use with ACCESS IP Codecs

The following manuals are available: ACCESS Rackmount - ACCESS 2USB - ACCESS Mixer

You may also find these QuickStart guides helpful: ACCESS Rackmount - ACCESS 2USB

ACCESS Algorithms

The ACCESS codec includes the following algorithms as standard:

Algorithm Audio Bandwidth Data Bitrate Coding Delay
HE-AAC 20kHz mono 32kbit/s 600ms
20kHz stereo 48kbit/s 600ms
20kHz dual mono 64kbit/s 600ms

HEv2-AAC 20kHz 18-48kbit/s 300ms

AAC 20kHz 64-256kbit/s 300ms

AAC-LD 20kHz mono 64kbit/s 80ms
20kHz stereo 96kbit/s 80ms
20kHz dual mono 128kbit/s 80ms

AAC-ELD 20kHz 24-96kbit/s 50ms

Linear uncompressed 20kHz mono 788kbit/s 40ms
20kHz stereo 1536kbit/s 40ms

FLAC 20kHz mono ~540kbit/s* 26ms
20kHz dual mono ~1080kbit/s* 26ms
15kHz mono ~360kbit/s* 26ms
15kHz dual mono ~720kbit/s* 26ms

G.711 µ-law & a-law 300Hz-3.4kHz mono 64kbit/s 80ms

G.722 7kHz Mono 64kbit/s 80ms

OPUS Mono 48kbps 48kb/s 41ms
Mono 56kbps 56kb/s 41ms
Mono 64kbps 64kb/s 41ms
Stereo 64kbps 64kb/s 41ms
Stereo 96kbps 96kb/s 41ms
Stereo 128kbps 128kb/s 41ms
CBR Mono 48kbps 48kb/s 41ms
CBR Mono 64kbps 64kb/s 41ms
CBR Stereo 64kbps 64kb/s 41ms
CBR Stereo 96kbps 96kb/s 41ms
CBR Stereo 128kbps 128kb/s 41ms

*FLAC bandwidth is variable and based on audio input

Provides near transparent audio at a range of data rates. AAC has been extensively tested by critical listening studies and has been judged to be virtually indistinguishable from the original audio.

Enhances the AAC standard by adding Spectral Band Replication. This is a way of delivering equivalent performance to AAC at lower rates. SBR is applied to high frequencies of audio, while normal AAC is applied to the lower frequencies. This is the standardized version of what has been known in the industry as aacPlus.

Enhances the HE-AAC standard by adding a special form of parametric stereo coding to further reduce data rates.

Requires higher data rates but provides near transparent voice and music with low delay.

Combines the best aspects of low-delay audio coding with Spectral Band Replication to reduce bitrate. This combination creates a coding algorithm that is uniquely suited to real-time IP transmission. Using AAC-ELD with ACCESS allows full-fidelity high quality audio transmission at a data rate that easily fits into satellite and 3G wireless upload channels. One way ACCESS transmission delay using AAC-ELD is an easily-managed 50 milliseconds.

Linear PCM
Does not compress audio at all and uses 48kHz sampling to provide low-delay transparent audio but with large data throughput. Mono mode requires a network capacity of 804kb/s whilst stereo (dual mono) requires in excess of 1.5Mb/s.

Compresses the audio data using a low-delay loss-less algorithm that usually removes some 30-40% of the network data compared with PCM, without introducing any coding artefacts. The actual data rate is variable based on the complexity of the coded audio.

G.711 – µ-law & a-law
The coding algorithms used by standard digital POTS/PSTN calls, providing normal "telephone quality" 300Hz-3.4kHz audio. These algorithms are included for compatibility with SIP-style VoIP 'phones and codecs.

The coding algorithm traditionally used by broadcasters over ISDN for sport and news commentaries and providing 7kHz low-delay speech and music. This algorithm is also included for compatibility with SIP-style VoIP 'phones and codecs.

A new flexible audio format that is taking Audio over IP by storm, ACCESS units on update 3.0 or higher receive support for this format. Opus is a low delay, low bitrate and high quality audio codec. This audio format is utilised by our CallMe Internet Codec Service, which links smartphones, tablets and computers to your studio codec.

Specifications - Rackmount
Audio Connections
Analogue inputs Balanced stereo XLR connectors
Line level (0dBu)
Analogue outputs Balanced stereo XLR connectors
Line level (0dBu)
Digital input AES3 on XLR connector
Digital output AES3 on XLR connector
Other Connections
Ethernet 2x RJ45 10/100BaseT
Telephone line RJ11 6-pin modular jack
Contact closures 4 on DB-9 male
Serial port for ancillary data DB-9 female
VGA monitor port DB-15 female
2 USB ports Type A
WiFi adapters, 4G / 3G dongles (subject to driver availability
Keyboard or mouse
PS/2 port Keyboard or mouse
Front-panel indicators Stereo input and output LED level meters
Status LED
Power LED
Requirements 120/240V AC, 60/50Hz, 50 watts
Connector 3-pin IEC
Size 1-U x 19" Rackmount - 483 x 45 x 229mm (19" x 1.75" x 9") approx
Weight 4kg (9lbs) approx
Specifications - Portable
Audio Connections
Analogue inputs Balanced mono XLR connector, mic / line switchable with volume control and software-selectable 12V phantom power
Unbalanced stereo 3.5mm jack, line level
Analogue output Unbalanced stereo 3.5mm jack, line level
Headphone monitor output Unbalanced stereo 3.5mm jack with volume controls for local and return audio
Cellular 'hands-free' input / output 3.5mm jack
Other Connections
Ethernet RJ45 10/100BaseT
Contact closures 4 on 9-pin mini-DIN connector
Serial port for ancillary data 9-pin mini-DIN connector
2 USB ports Type A
WiFi adapters, 4G / 3G dongles (subject to driver availability
Keyboard or mouse
Connector 5-pin mini-DIN connector
Battery Lithium-Ion rechargeable with charger built into ACCESS Portable unit
Battery life 7 hours continuous use / 5 hours with optional mixer (approx)
Mains power supply 93-250V AC, 50-60Hz with IEC-F mains input - provides 15V DC for ACCESS at 2 amps
Specifications - Optional mixer
Audio Connections
Audio inputs 5x balanced mono XLR connectors
Mic / line switchable with software-selectable 12V phantom power
Input 5 can be software-configured as a producer cue channel
Audio outputs 5x ¼" TRS headphone jacks
Audio Controls
Level Level adjustments for audio input, headphone local audio and headphone return audio for each channel
Stereo balance / pan Parametric pan controls for channels 1 to 4 to accommodate two stereo inputs
Power requirements 12V DC supplied by ACCESS Portable
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