1. Manuals
  2. Brands
  3. Comrex Manuals
  4. Conference System
  5. Access NX
  6. Product manual

Comrex Access NX RACK Product Manual

Hide thumbs Also See for Access NX RACK:
Table of Contents

Advertisement

Quick Links

Download this manual See also: Product Manual
Product Manual

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the Access NX RACK and is the answer not in the manual?

Questions and answers

Subscribe to Our Youtube Channel

Related Manuals for Comrex Access NX RACK

Summary of Contents for Comrex Access NX RACK

  • Page 1 Product Manual...

  • Page 2: Table Of Contents

    ACCESS NX RACK MANUAL I. INtroductIoN ApplIcAtIoNs AudIo codINg trANsmIssIoN modes ANd delAy swItchboArd server crosslock AddItIoNAl FeAtures Aes67 protocol html5 II. dIAgrAms ANd INstAllAtIoN reAr pANel dIAgrAm ANd descrIptIoNs FroNt pANel dIAgrAm ANd descrIptIoNs moNo vs. stereo pINouts - bAlANced AudIo pINouts - coNtAct closures pINouts - serIAl port III. quIck stArt-mAkINg coNNectIoNs wIth Nx rAck 17 ACCESS NX Rack •July 2019...
  • Page 3 quIck stArt-mAkINg coNNectIoNs wIth Nx rAck more About proFIles usINg the coNsole mAkINg swItchboArd coNNectIoNs receIvINg INcomINg coNNectIoNs Iv. usINg the devIce mANAger progrAm updAtINg FIrmwAre usINg devIce mANAger Network recovery mode v. coNFIgurINg Nx rAck: coNsole INterFAce logIN INterFAce pAge sectIoNs coNNectIoNs tAb dAshboArd tAb perFormANce tAb ActIve coNNectIoNs codec chANNel FIeld crosslock FIeld crosslock settINgs proFIle mANAger tAb...
  • Page 4 buIldINg A proFIle proFIle settINgs: locAl & remote eNcoders AdvANced locAl & remote optIoNs system settINgs tAb securIty settINgs coNNectIoNs coNtAct closures swItchboArd server crosslock vpN system clock AlterNAte modes Aes67 system AdvANced system settINgs securIty coNNectIoNs AuxIlIAry serIAl swItchboArd server crosslock vpN brIc NormAl settINgs http modem stANdArd rtp settINgs ebu3326/sIp settINgs...
  • Page 5 tcp settINgs mIscellANeous Network mANAger tAb etherNet port settINgs Network locAtIoNs wlAN AdApter 3g/4g coNNectIoNs AdvANced etherNet port settINgs vI. Aes67 coNNectIoNs settINg up For Aes67 clockINg Aes67 INput settINg INput delAy Aes67 output Aes67 AdvANced optIoNs INputs outputs vII. mAkINg crosslock coNNectIoNs how crosslock works: A brIeF overvIew mAkINg ANd breAkINg coNNectIoNs creAtINg ANd coNNectINg to remotes...
  • Page 6 creAtINg A New remote coNNectINg ANd dIscoNNectINg pAssword FIlterINg bAckup remote FAll ForwArd how crosslock works: A closer look multI-Network support mAkINg crosslock coNNectIoNs usINg swItchboArd mAkINg mANuAl crosslock coNNectIoNs hotswAp dAtA usAge setup vIII. mAkINg coNNectIoNs wIth swItchboArd loggINg IN ANd settINg up swItchboArd creAtINg users coNtAct lIsts FollowINg coNtAct lIsts shAres mANAgINg multIple coNtAct lIsts bulk ActIoNs For coNtAct lIsts swItchboArd theory ANd coNcepts...
  • Page 7 Ix. operAtINg Nx rAck IN A 24/7 eNvIroNmeNt AlwAys coNNect to bAckup remote x. pots coNNectIoNs pots codec setup For Access compAtIbIlIty usINg Nx rAck wIth pots rAte drop vs. retrAIN troubleshootINg A pots coNNectIoN xI. About the AlgorIthms AAc he-AAc he-AAcv2 lINeAr pcm* FlAc* g.722 opus AlgorIthm codec proFIles...
  • Page 8 xII. multI-streAmINg multI-streAmINg ArrANgemeNts Nx rAck INItIAtes the cAll Nx rAck receIves the cAll usINg crosslock wIth multI-streAm coNNectIoNs 83 xIII. Ip multIcAst multIcAst proFIles settINg up A multIcAst remote tIme-to-lIve chANgINg port Numbers For multIcAst xIv. streAmINg server FuNctIoN decodINg A streAm sImultANeously coNNectINg Access rAcks ANd streAmINg xv. mAkINg ebu3326/sIp compAtIble coNNectIoNs more About ebu3326 ebu3326 IN Access rAck ebu3326/sIp modes...
  • Page 9 uNregIstered mode regIstered mode sIp servers sIp urIs regIsterINg wIth A server mAkINg regIstered sIp cAlls AdvANced ebu3326/sIp topIcs sIp troubleshootINg outgoINg cAll Issues INcomINg cAll Issues solutIoNs stuNNINg success FIx oF lAst resort xvI. lIceNse & wArrANty dIsclosures For Nx rAck lIceNse wArrANty xvII. swItchboArd trAversAl server dIsclAImer trAversAl server dIsclAImer xvIII. coNFormIty ANd regulAtory INFormAtIoN...
  • Page 10 supplIers’ declArAtIoN oF coNFormIty ec declArAtIoN oF coNFormIty For r&tte dIrectIve us & cANAdA regulAtory INFormAtIoN xIx. AppeNdIx A: Ip compAtIbIlIty 101 xx. AppeNdIx b: uNIdIrectIoNAl Networks 103 stANdArd rtp settINgs decode sIde settINgs oNly eNcode sIde settINgs oNly Full-tIme or trIggered coNNectIoNs xxI. AppeNdIx c: INFormAtIoN For It mANAgers 104 INcomINg servIces outgoINg servIces...
  • Page 11 Each unit we ship has been individually and thoroughly tested. Comrex stands behind its products. We promise that if you call us for technical assistance, you will talk directly with someone who knows about the equipment and will do everything possible to help you.

  • Page 12: Introduction

    INTRODUCTION Congratulations on purchasing the Comrex ACCESS NX Rackmount codec! The NX Rack leverages the core functionality of the original ACCESS Rack first introduced in 2006, quickly becoming the world’s leading IP audio codec. The NX Rack carries the ACCESS line forward, promoting an entirely new hardware and software platform.

  • Page 13: Switchboard Server

    Enhanced statistics and diagnostics • Use of CrossLock is optional, and requires a Comrex codec running 4.x-level firmware on each end of the link. CrossLock connections can be made via the Comrex Switchboard function (see previous section) or manually. For manual connections, CrossLock requires extra settings to assure connections are only made within your known group of codecs.

  • Page 14: Diagrams And Installation

    NX RACK DIAGRAMS AND INSTALLATION II. 3 & 4 5 & 6 FIgure 1 reAr pANel dIAgrAm ANd descrIptIoNs AC Input - An IEC connector for the main power. NX Rack works on worldwide AC power at 110-240VAC 50-60Hz, auto detecting. Analog/AES3 Input Switch - This switch determines whether the Line In Left/AES3 In XLR connector is used for analog or AES3 digital audio input.

  • Page 15: Front Panel Diagram And Descriptions

    FIgure 2 FroNt pANel dIAgrAm ANd descrIptIoNs Send - Peak meter that displays the level of audio sent locally into the NX Rack, regardless of an active connection. Proper level is indicated by peaks driving the Green and Yellow LEDs, while avoiding lighting the Red LEDs (which indicates clipping). Receive - Peak meter that displays the level of audio being received from the far end when a connection is active.

  • Page 16: Pinouts - Contact Closures

    pINouts - coNtAct closures Contact Closures are available via the male 9-pin GPIO port on the back of the NX Rack. Inputs are triggered by shorting the respective input to Pin 5. Outputs consist of an open collector circuit which, when inactive, will offer a high-impedance path to Pin 5 and, when active, will offer a low impedance path to Pin 5.

  • Page 17: Quick Start-Making Connections With Nx Rack

    IP Address of the NX Rack, open any computer’s web browser on the same network as NX Rack. Type the IP address in the browser URL to navigate to the NX Rack’s web interface. Log in to NX Rack with any user name and, if not changed, the default password “comrex”. FIGURE 3...

  • Page 18: Making Switchboard Connections

    Making Switchboard Connections On the Web Interface, select the “Connections” Tab. This Tab will populate with a list of available remote codecs to call. When the NX Rack is “synced” with Switchboard, connections to other codecs in a user’s Switchboard account are simple. Go to the listings on the bottom that appear with a “Gear” icon on the left side. Any units with a Green Gear icon are available for Switchboard connections.

  • Page 19: Using The Device Manager Program

    IP configuration. Please note: In order to configure a ACCESS NX Rack unit for the first time (without knowing the unit’s IP address), Device Manager must be run on a computer located on the same network (e.g., WiFi or physical LAN connection) as the unit itself.
  • Page 20 FIgure 7 toolbox logIN Generally, it is recommended to configure the Ethernet port of an ACCESS NX Rack for a static IP. This will facillitate access to the Web-based Interface with a browser and allow for easier configuration of routers or firewalls (if necessary). If the NX Rack is to be installed on a managed LAN, Comrex recommends consulting with the IT services provider about obtaining a static IP address.

  • Page 21: Updating Firmware Using Device Manager

    FIgure 8 Network coNFIgurAtIoN updAtINg FIrmwAre usINg devIce mANAger While Device Manager is open and synced to a codec, it’s a good time to check to see if an update is available for the product. To do this, select the Firmware tab, shown in Figure 9 below. The unit’s current firmware and the most recent version of firmware for the unit are listed at the top of the tab (1 in Figure 9).

  • Page 22: Network Recovery Mode

    FIgure 9 FIrmwAre tAb Network recovery mode Since the Ethernet settings are made with a web connection, keying in incorrect static IP information can result in losing access to the Network Manager interface entirely. If this happens, it is possible to be “locked out” of the unit -- i.e., unable to log in.
  • Page 23 FIgure 10 Network recovery mode...

  • Page 24: Configuring Nx Rack: Console Interface

    2) The console interface does not require a login procedure. logIN Upon connection to the NX Rack, a login screen will appear, Figure 11. Any username can be chosen with the default password: comrex. This will access the Main User Interface display. FIgure 11 web INterFAce logIN INterFAce pAge sectIoNs There are two parts to the primary interface screen (Figure 12): Main Audio Meter (1): This meter displays audio leveling for active connections to the NX Rack.

  • Page 25: Connections Tab

    In the event that a stored unit is no longer desired, they can be deleted through the Trash Icon option. The Connections tab will display IP and Status information of a remote Comrex codec when it has initiated a connection to the NX Rack.

  • Page 26: Performance Tab

    FIgure 13 dAshboArd tAb 1. The audio level meters give a quick indication of send and receive levels. 2. The Contact Closure section gives a visual indication of the state of each input (local) and output closure (remote). The input closure boxes also function as buttons to trigger closures locally. 3.

  • Page 27: Codec Channel Field

    FIgure 15 jItter/pAcket error grAph The left graph represents the work of the Jitter Buffer Manager. The area of most interest is the light blue area as shown in Figure 15, which illustrates a spread of jitter values (referenced to the current playout pointer) over the last second.
  • Page 28 The CrossLock Stats are similar to the information available on the Active Connections graph, which shows streaming performance without regard to the CrossLock layer. The CrossLock Stats show finer details about network performance in both directions than can be obtained through the Active Connections graph. CrossLock stats are shown for both the data being transmitted from the local codec and the data being received by the local codec.

  • Page 29: Crosslock Settings

    crosslock settINgs Clicking the CrossLock Settings field during an active connection will display the CrossLock sliders. There is a slider available for transmit and receive operation. For most CrossLock connections, the sliders should be left at their default Automtic Delay Mode settings. But during connections on unusual networks, these sliders are designed to quickly adjust the current delay settings.

  • Page 30: Profile Manager Tab

    Furthest left is the red zone, which indicates a buffer level that is too low for stable transmission. The yellow zone indicates a delay buffer that may have stability issues, and the green zone indicates a buffer level that should provide stability.

  • Page 31: Building A Profile

    Profile. Select it to populate a set of options, starting with the profile Name (2 in Figure 22). Here the profile can be renamed to something easier to remember. Next is the Channel option (3 in Figure 22), which allows for selecting between a standard Comrex IP connection (BRIC normal) or one of the other connection modes offered by NX Rack.

  • Page 32: Advanced Local & Remote Options

    These advanced options are a means of overriding these defaults, and Comrex recommends that users take care when changing them. Note that when it comes to settings that effect the jitter buffer manager, local settings affect the decoder on the local side, and remote settings affect the decoder on the remote end.
  • Page 33 buffer size to compensate. Fixed Delay: This option simply sets the Delay Cushion and Delay Limit at a similar value, so that the delay buffer is defined to the chosen value and will not increase or decrease significantly. Delay Cushion: The jitter buffer manager works to keep absolute delay to a minimum. Some applications are not delay sensitive and rely less on the jitter buffer manager.

  • Page 34: System Settings Tab

    automatically and with no audio interruption. Step down congestion avoidance is not enabled in the Linear PCM mode. UDP Reliability – UDP, the Internet protocol used by BRIC Normal connections, does not have any inherent error correction capability. UDP reliability adds an intelligent algorithm that requests packet resends when appropriate above the base UDP level.

  • Page 35: Security Settings

    Remote Control Password: This allows for a defined password for the web GUI and firmware updates. The default password is comrex (lower case). The remote control and firmware updating functionality can be disabled completely by disabling the Remote Control option.

  • Page 36: Crosslock Vpn

    NTP Enabled: Enables the use of NTP network time synchronization. This setting is set to Yes by default. NTP Server: This allows users to set the address of the NTP server. This is set for 0.comrex.pool.ntp.org by default. Timezone: Users can set their Timezone in this setting. This allows for inputting a User’s Timezone by Region, Country, and Timezone.

  • Page 37: Aes67 System

    • Use SIP Proxy: This option determines whether the SIP function is “registered” to a SIP cloud server. If this setting is enabled the address, user name, and password for the proxy must be added in the relevant fields. • SIP Proxy Address: IP address or URL of the SIP proxy used. • SIP Username: Username for logging into registered SIP server;...

  • Page 38: Auxiliary Serial

    Even. swItchboArd server Switchboard Address: Displays IP address of the Switchboard Server. Default is ts.comrex.com. STUN Server: Displays IP address of the STUN Server. Default is stun. comrex.com. Switchboard Port: Configures the TCP port of the Switchboard Server. This is set to TCP 8082 by default.

  • Page 39: Bric Normal Settings

    NX Rack. An outgoing call must be made to a specific port number in the form of IP-ADDRESS:PORT#. For example, dialing port UDP 5004 on the Comrex test line is formatted 70.22.155.131:5004.

  • Page 40: Standard Rtp Settings

    ebu3266/sIp settINgs IP Port: The port used by the SIP negotiation channel when using EBU3326/SIP Mode. If this port is changed, it’s likely to break compatibility with other manufacturer’s codecs. User Agent Whitelist: List of SIP user agents that are allowed to communicate. Only SIP agents on this list can communicate with the NX Rack.

  • Page 41: Miscellaneous

    WiFi and Cellular adapters used to make a Network connection. Here the IP and SSID settings for these network connections can be configured. Because there may be bandwidth, firewall, and/or security concerns involved when installing NX Rack on a managed LAN, Comrex strongly recommends that users consult their IT manager in environments where these concerns are present.

  • Page 42: Ethernet Port Settings

    Active Network Location section of the device settings will note which network configurations the unit is using for the Ethernet Port. By default, the Active Network Location will be populated with the “Default” location. This “Default” location is configured for DHCP and is initially enabled on all new units. FIgure 25 etherNet port deFAult settINgs For users that wish to have a Static IP address for their units, this can be configured by editting the settings for the “Default”...

  • Page 43: Wlan Adapter

    and Gateway settings. If selecting a Static IP address, make certain to enter the unit’s new IP address, its Netmask, and its Gateway Address, as well as at least one DNS Server Address. FIgure 27 etherNet port deFAult settINgs Once a Network Location has been added, it can be easily implemented through the Active Network Location selection in the Adjust Device Settings.

  • Page 44: 3G/4G Connections

    When setting up a WiFi connection, users will require the use of a USB WiFi adapter to begin making connections. Once this has been installed, the adapter will populate in the Select Network Device section of the Network Manager Tab as the WLAN Adapter (Figure 28). This adapter must be Enabled prior to using or scanning it. The WLAN Adapter can be enabled by selecting it in the list and selecting “Enabled”...
  • Page 45 Preserve After Reset: This option ensures that changes to the unit’s network configuration will be preserved even if the device is reset to factory defaults. This setting is disabled by default, however, and Comrex advises users to be cautious when enabling it. If the Ethernet parameters are set incorrectly it is possible to be locked out of the NX Rack, and will then have to use the Device Manager program‘s Network Recovery Mode (discussed in the previous...

  • Page 46: Aes67 Connections

    AES67 CONNECTIONS vI. AES67 is an Audio-over-IP (AoIP) standard for intra-studio audio routing. It’s not intended to be an out-of-studio distribution technique, but rather to replace the Analog/Digital audio ports with an Ethernet cable. This makes audio wiring simpler (standard Ethernet cable) and moves the routing of audio into the networking domain. While AES67 is the standard, several pre-standard systems have gained popularity.

  • Page 47: Setting Up For Aes67

    • NX Rack can only be set entirely for AES67 or Analog/AES3 operation. It’s not possible to mix modes for input/output audio. All XLR ports on NX Rack are entirely disabled in AES67 mode, including outputs. SETTING UP FOR AES67 AES67 settings are located in the System Settings tab on the configuration web page.

  • Page 48: Aes67 Input

    AES67 compliant. If you don’t know how to do that, the system specific cheat sheets available on the Comrex web site can help. Once you’re aware that the NX input stream is active, choose the Input 1 setting in the AES67 options, and select “Source”.

  • Page 49: Setting Input Delay

    This requires a way to monitor the NX Rack audio input. This is most easily accomplished by establishing a connection to another Comrex codec and monitoring the audio output of that codec.

  • Page 50: Aes67 Output

    AES67 OUTPUT When AES67 is enabled on an NX Rack, an AES67 output stream is automatically created. This stream has the following parameters: 2 channel • 48KHz sampling • 1mS packet timing • SAP and Ravenna Advertisement • Multicast destination address 239.1.x.x (Where x.x are the last two decimal digits of the •...

  • Page 51: Outputs

    OUTPUTS TTL: Outgoing packets have a Time-To-Live value assigned to them. Some networks may require this value be lower or higher than the default of 15. Consult your IT department in the unusual case this must be changed. DSCP: This is a flag applied to outgoing packets that tells your switches about priority. The AES67 default is 34, and should be changed only when special requirements exist.

  • Page 52: Making Crosslock Connections

    MAKING CROSSLOCK CONNECTIONS ON NX RACK vII. Comrex first introduced CrossLock -- its technology that creates an additional reliability layer to ensure quality broadcast connections -- with version 4.0 firmware in 2016. As an increasing majority of users updated their units to CrossLock-capable firmware, connections made using CrossLock became the norm for Comrex codecs and are considered standard in NX Rack and ACCESS Codec connections.

  • Page 53: Creating And Connecting To Remotes

    9001 in default connections. For users using ports that are not UDP 9000 for BRIC Normal connections, the “X+1 Rule” applies for setting up both Crosslock and traffic to Comrex equipment. Assuming that network and physical I/O connections to NX Rack are completed, creating connections to remote units requires inputting the device information into the Connections tab of the User Interface.

  • Page 54: Connecting And Disconnecting

    field should be left blank unless the remote has password filtering enabled for incoming calls. If this is the case, a password will be required to establish a connection. FIgure 37 edIt remote settINgs Remote devices require selection of an algorithmic codec profile (1 in Figure 37). The NX Rack includes several factory profiles to choose from, each of which enabling a full-duplex link.

  • Page 55: Password Filtering

    the connection (Figure 39). If the connection fails, the reason for the connection failure will be shown in the State column. When the remote connection succeeds, the encoder and decoder mode will be reflected in the Rx Status/ Tx Status column. To end a connection, highlight the remote and select Disconnect. FIgure 39 ActIve remote coNNectIoN pAssword FIlterINg The Connection Password function can be used to filter incoming connections.

  • Page 56: Fall Forward

    The Backup Remote feature works in conjunction with a remote’s Local Timeout parameters defined in the primary remote’s profile. NX Rack can sense an IP Connection failure, and will wait the defined Local Timeout parameter in the primary remote’s profile. If the connection is restored during this time, no backup will occur. If the timeout lapses without re-connection to the primary remote, NX Rack will automatically connect to the designated Backup Remote.

  • Page 57: Making Manual Crosslock Connections

    Ethernet port MAC address. So to connect via CrossLock, each unit must know all other units’ IP and MAC addresses. Once the IP and MAC addresses are in defined in Switchboard, connections can be made without further input on either end. For more information on using Switchboard, see the Switchboard section on page mAkINg mANuAl crosslock coNNectIoNs...

  • Page 58: Hotswap

    Hotswap activity occurs. If the Hotswap function engages to a cellular network, much more data will be used while the primary network is down. Regardless of how Hotswap is used or set up, Comrex assumes no liability for data overage charges, even in the event of software bugs or any other failure of hardware or software.
  • Page 59 FIgure 43 hotswAp Network devIce setup Here the backup network can be selected. This network’s options can be expanded using the “Show Advanced” button, which will reveal additional configuration options. Find the option labeled “Use with CrossLock” and change the default from “yes” to “backup” (Figure 43).
  • Page 60 FIgure 45 hotswAp cc uNIt Finally, set one of the contact closures to sound an alert when the HotSwap function is engaged. Still in the CrossLock settings, choose “HotSwap CC unit”. Choose whether the contact closure output triggers on the local, remote, or both codecs (Figure 45). Select “Save Settings” then click “Back”. FIgure 46 hotswAp cc INdIcAtor Next choose “HotSwap CC Indicator”...

  • Page 61: Making Connections With Switchboard

    MAKING CONNECTIONS WITH SWITCHBOARD vIII. The Switchboard Traversal Server is a service built and maintained by Comrex on the public Internet that provides users a directory of other users; facilitating connections to devices that would normally have trouble accepting incoming IP connections. Use of Switchboard is free and comes activated from the factory. Use the instructions in the user interface chapters of this manual to configure Switchboard on the NX Rack unit.

  • Page 62: Creating Users

    creAtINg users It is possible to add additional Switchboard users who can access the Switchboard interface. This is done via the Users tab at the top of the main codec list (Figure 49). This allows for the creation of accounts for users that can later be deleted.

  • Page 63: Following Contact Lists

    NOTE: Assigning a Contact List to a codec determines what gets displayed in its own list. It does not have any impact on how that codec is displayed on other devices. FollowINg coNtAct lIsts Each unit also has the ability to Follow a Contact List. This is a view-only function that allows a codec to see the status and presence of units in a Contact List.

  • Page 64: Shares

    FIgure 53 Follow coNtAct lIst On the next screen, check the Contact List(s) that you want this codec to Follow and press “Update Contact List” (Figure 53). One important point to remember: Following a Contact List on a codec only determines which units get displayed on that codec’s own list.
  • Page 65 FIgure 57 shArINg AccouNts Finally, while it is possible to delete Shares, Comrex recommends disabling them instead. This will stop the Share and won’t require any future work to recreate it. To disable a Share, simply click the orange Disable button on the bottom right of the Share edit page (Figure 58).

  • Page 66: Managing Multiple Contact Lists

    FIgure 58 dIsAble shAre mANAgINg multIple coNtAct lIsts While most people will only use the default Contact List, it is possible in Switchboard to create and Follow multiple Contact Lists as well as to manage them from a codec’s user interface. FIgure 59 multIple coNtAct lIsts If multiple Contact Lists have been designated as “Followed“ on a unit’s Switchboard interface, each Contact List will appear at the bottom of the Connections tab (Figure 59).

  • Page 67: Bulk Actions For Contact Lists

    Please note: Only Contact Lists a codec is actively following can be viewed from that codec. bulk ActIoNs For coNtAct lIsts It is possible in Switchboard to perform actions that impact all codecs in a given Contact List in a single step called a Bulk Action.
  • Page 68 Step 2: Select the Target Codecs Next choose which list of codecs to target with this Bulk Action (Figure 63). FIgure 63 bulk devIce selectIoN After completing this step, specify whether to target the units that are a part of a Contact List or the units that are Following that list (i.e., the option in the yellow-outlined box on the middle-left of the above figure).

  • Page 69: Switchboard Theory And Concepts

    swItchboArd theory ANd coNcepts Switchboard is useful because it’s not always simple to connect two devices over the internet which are essentially “peers”. There are two major reasons for this. First, to initiate a stream to a device over the internet requires knowing its IP address. This is the number that gets applied to the destination field of the IP packet, so internet routers can determine how best to send it along its way.
  • Page 70 The challenges of connecting codecs behind NAT routers will be addressed in more detail shortly. For now, remember that one of the problems NAT servers add is that private IP addresses delivered to codecs (and the only addresses of which the codecs are aware) have no bearing on the public addresses seen from the internet. In extreme scenarios, several layers of address locality can be stacked, assuring that the IP address assigned to a device is several degrees removed from the public IP address used for connections.
  • Page 71 This can work well for fixed installations, but it’s not always an easy task to obtain that kind of security access on corporate routers. Additionally, forwarding functions are implemented differently depending on the hardware. One can easily imagine the complications of obtaining or managing port forwarding on the LAN when arriving at a new remote venue.
  • Page 72 Network Address Translation (NAT) refers to the ability of a router to translate requests from computers (or codecs) within its LAN onto the public internet. On its most basic level, this involves replacing the private “source” or return IP address in each packet with the true public IP and remembering where that packet was sent. This insures that any response can be forwarded back to the proper device.

  • Page 73: Operating Nx Rack In A 24/7 Environment

    OPERATING NX RACK IN A 24/7 ENVIRONMENT Ix. NX Rack can be configured for “always on” operation. This allows for constant STL communication and operations requiring long term connections. In BRIC Normal mode (the default mode of operation), NX Rack transfers all its audio data via the UDP 9000 protocol.

  • Page 74: Backup Remote

    FIgure 68 AlwAys coNNect to settINg bAckup remote NX Rack has an additional option for constant connections. When building a remote entry, a field is available for backup options, one of these options is “Keep Retrying This Remote” mode. In a similar fashion, using this mode will allow the unit to disregard the timeout value and keep a persistent connection attempt.
  • Page 75 Additionally, there is a box in the Change Remote Settings tab labeled Automatically fall forward. If this box is checked, the system will constantly attempt to reconnect the primary remote while connected to the fallback remote. If connection is successful, the connection to the “Fallback” will be terminated.

  • Page 76: Pots Connections

    POTS CONNECTIONS NX Rack is capable of connections over modem links. This mode emulates the function of Comrex POTS (Plain Old Telephone Service) codecs, which have been used for years to deliver high quality audio over standard, dial-up telephone lines. This mode provides for a point-to-point connection between the codecs (i.e. no internet NX Rack is used) and the call is placed directly from one NX (or legacy codec) to the other.
  • Page 77 FIgure 70 coNNectIoNs tAb durINg AN ActIve pots cAll Selecting Rate Drop will force the system to drop to the next lowest connect rate at any time. Audio transfer will be interrupted momentarily while the units negotiate the new connect rate. Alternately, Retrain will force the system to initiate the entire training sequence again (the “chat” sounds heard at the beginning of a call). Audio loss will occur for a longer time (approx.
  • Page 78 • At minimum, connect a few minutes before airtime to assess the connection quality. Setting a MaxRate on the POTS codec, is highly recommended. MaxRate usually should be set at a level or two below the maximum unrestricted rate. This will provide a “guard band” against noise and distortion which may cause errors on the line.

  • Page 79: About The Algorithms

    ABOUT THE ALGORITHMS xI. When building profiles for NX Rack and remote devices, there are several different audio encoder options to use for each direction of the link. Different audio encoder options each have advantages and disadvantages depending on the situation. The following is a refresher on audio codec algorithms to assist in making the best choice. This algorithm is a highly regarded standard for compressing audio to critical listening standards.

  • Page 80: Flac

    Special CBR modes are offered for compatibility with Tieline products - avoid these in other applications. Due to its versatility in audio quality and low networking drain, Opus is the default profile for Comrex codecs. *Linear PCM and FLAC are only supported for CrossLock connections on devices running 4.3-p4 firmware or...

  • Page 81: Algorithm Codec Profiles

    Algorithm Comparison Chart for ACCESS NX Rack Required Coding Audio Bitrate Delay Bandwidth 64 kb/s 69 ms 20 kHz D1 Mono 96 kb/s 69 ms 20 kHz D2 Stereo 128 kb/s 69 ms 20 kHz D3 Dual Mono allows independent programming to be sent on both L&R channels...

  • Page 82: Multi-Streaming

    MULTI-STREAMING xII. NX Rack supports the ability to run one encoder per box, but this single encoder stream may be sent to up to three destinations simultaneously. This capability is referred to as a Multi-Stream, as the encoder creates a separate but identical outgoing stream to each decoder.

  • Page 83: Multi-Streaming Arrangements

    Crosslock functionality in multi-streaming has been introduced with NX Rack. Previous Comrex Access Racks did not support Crosslock VPN when performing a Multi-Stream. With the introduction of NX Rack, the added broadcast...

  • Page 84: Ip Multicast

    IP MULTICAST xIII. IP Multicast is an efficient way of delivering NX Rack digital audio streams to multiple locations. This involves relying on the network to distribute the stream to the locations that require it, rather than creating an independent stream for each user.

  • Page 85: Setting Up A Multicast Remote

    The important settings for Multicast are: • Sender/Receiver: Determines whether this particular NX Rack is designed to generate and encode the IP Multicast stream (send) or decode one (receive). • Encoder Type: Determines the algorithm format of stream to be used by the Multicast encoder - not relevant for decoders.

  • Page 86: Streaming Server Function

    STREAMING SERVER FUNCTION xIv. NX Rack has the ability to act as a streaming server, delivering AAC and HE-AAC to compatible PC based media players. Currently tested media players include WinAmp, VLC and Windows Media Player 12 and up. By default, streaming server functionality is turned off. To enable it, go to the System Settings tab of the User Interface and choose HTTP Settings option.

  • Page 87: Decoding A Stream

    (using the actual IP address, of course) sImultANeously coNNectINg Nx rAcks ANd streAmINg NX Rack can stream while connected to another Comrex codec in BRIC Normal mode. If the BRIC connection is using an AAC algorithm supported by players, when a stream is requested it will be delivered using the same encoder as the BRIC connection, regardless of the HTTP settings.

  • Page 88: Making Ebu3326/Sip Compatible Connections

    MAKING EBU3326/SIP COMPATIBLE CONNECTIONS xv. Comrex codecs (and many other brands) have a set of protocols that allow easy IP connections between units. In general, when connecting between Comrex hardware, it’s best to use these proprietary modes to take the most advantage of the features of the product.

  • Page 89: Ebu3326/Sip Modes

    URIs consist of a SIP user name, followed by a domain, delineated with the @ symbol, like an email address. Comrex’s Iptel user URI would be comrex_user@iptel.org. Comrex devices do not use the designation “sip:” before a SIP address.
  • Page 90 • The password on the SIP account Figure 77 shows how this information can be applied: enabling the Use SIP Proxy option under EBU 3326/SIP on the Systems Settings tab. FIgure 77 ebu3326/sIp settINgs Once this information is correctly entered, a new field appears in the “Registration Status” box located on the Connections tab (Figure 78).

  • Page 91: Making Registered Sip Calls

    The basic entries provided will allow support for the vast majority of EBU3326/SIP based applications. There are inevitably situations where the defaults won’t work, however. Comrex has provided some advanced options that can help. These options are located in the Systems Settings and can be made visible by selecting the Advanced box: • IP Port: Universally, SIP connections are supposed to use UDP port 5060 to negotiate calls between...

  • Page 92: Sip Troubleshooting

    Incoming calls to codecs behind routers are complicated by the need to forward ports on the router to the codec. In the case of SIP, this must be three discrete ports (For Comrex codecs these are UDP 5060, 5014 and 5015)<6014 and 6015 with 3.0 firmware>.

  • Page 93: Stunning Success

    Another technique for working around the SIP-Router issue is by using a protocol called STUN. This can be enabled in Comrex codecs in the Advanced EBU3326/SIP options and allows for the codec to learn its public IP address. It does this by contacting a STUN server on the Internet (the default one is maintained by Comrex) and requesting its Public IP.

  • Page 94: License & Warranty Disclosures For Nx Rack

    Gnu Public License (GPL). For more information on GPL see http://www.gnu.org. As per the GPL, source code for this software is available on request from Comrex on CD-ROM or other electronic format. To obtain this software please contact our support department at +1 978 784 1776. We retain the right to charge a small handling fee for distribution of this software.

  • Page 95: Warranty

    During the warranty period, we will repair or, at our option, replace at no charge a product that proves to be defective, provided you obtain a return authorization from Comrex and return the product, shipping prepaid to Comrex Corporation, 19 Pine Rd, Devens MA 01434 USA. For return authorization, contact Comrex at 800-237-1776 or 978-784-1776 or email techies@comrex.com.
  • Page 96 OR CONSEQUENTIAL DAMAGE RESULTING FROM THE USE OF THE PRODUCT INCLUDING LOSS OF PROFITS, LOSS OF SAVINGS, LOSS OF USE OR INTERRUPTION OF BUSINESS EVEN IF COMREX CORPORATION OR ANY OF ITS SUPPLIERS HAS BEEN ADVISED OF THE POSSIBILITY OF SAME. IN NO EVENT SHALL COMREX CORPORATION AND/ OR ITS SUPPLIERS’...

  • Page 97: Switchboard Traversal Server Disclaimer

    Comrex provides this service, free of charge and at will. As such, Comrex offers no warranty as to availability of this server or of its function. Comrex reserves the right to discontinue availability of this service at any time. Comrex also reserves the right to remove any account from the server at http://switchboard.comrex.com at any time for...

  • Page 98: Conformity And Regulatory Information

    Date of Issue: January 23, 2006 Equipment: Comrex ACCESS NX Rack Comrex Corporation, located at 19 Pine Road, Devens, MA in the United States of America hereby certifies that the Comrex ACCESS NX Rack bearing identification number US:DXDMD01BACCRK complies with the Federal Communications Commission’s (“FCC”) Rules and Regulations 47 CFR Part 68, and the Administrative Council...

  • Page 99: Ec Declaration Of Conformity For R&Tte Directive

    19 Pine Road Devens, MA 01434 hereby declare on our sole responsibility that the product: Comrex ACCESS NX Rack Digital Audio Codec to which this declaration relates is in conformity with the essential requirements and other relevant requirements of the R&TTE Directive (1999/5/EC). This product is compliant with the following standards and other normative...

  • Page 100: Us & Canada Regulatory Information

    U.S. telephone company. Telephone line connections to the Comrex ACCESS NX Rack are made via an RJ11C jack. A plug and jack used to connect this equipment to the premises wiring and telephone network must comply with the applicable FCC Part 68 rules and requirements adopted by the ACTA.

  • Page 101: Appendix A: Ip Compatibility

    APPENDIX A - IP COMPATIBILITY xIx. The NX Rack is capable of encoding and decoding a choice of three different types of non-NX Rack streams: Standard RTP, Luci Live and Zephyr Xstream. The choice is exclusive -- i.e., you must set the NX Rack specifically for the type of stream you wish to be compatible with and you will remain incompatible with the other two types unless you change it.
  • Page 102 • Outgoing Connections: Build a profile using the Profile Manager on the NX Rack and select a Channel Mode of Standard RTP. Then choose an Xstream-compatible encoder for the outgoing call. The Xstream will control what type of stream, if any, is returned to the NX Rack. 3. Standard RTP: This mode is set to receive a basic, unformatted AAC stream within a standard RTP/UDP structure.

  • Page 103: Appendix B: Unidirectional Networks

    AppeNdIx b - usINg Nx rAck oN uNIdIrectIoNAl Networks xx. Under most circumstances, NX Rack requires an IP path in both directions for successful connections, even when audio is being sent only one-way. For networks that provide data only in one direction, it is possible to use Standard RTP mode to establish and maintain these links.

  • Page 104: Appendix C-Information For It Managers

    AppeNdIx c-INFormAtIoN For It mANAgers xxI. The purpose of this appendix is to describe all open ports and services available on the Comrex NX Rack. The Comrex NX Rack is a device designed to move real-time, wideband audio over IP networks. The main network interface is 1000BaseT-Ethernet.

Table of Contents