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Comrex ACCESS MultiRack Product Manual

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  • Page 1 Product Manual...

  • Page 2: Table Of Contents

    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 (Instance 1) Pinouts - Serial Port (Instances 2-5) ACCESS MultiRack • November 2019...
  • Page 3 III. Quick Start - Connections With MultiRack More About Profiles Using The Console About MultiRack Instances Making Switchboard Connections Receiving Incoming Connections IV. Using The Device Manager Program Updating Firmware Using Device Manager Network Recovery Mode V. Configuring MultiRack Login Controlling MultiRack Instances Instance Pages And Global Settings Interface Page Sections...
  • Page 4 Utilization Graph CrossLock Settings Profile Manager Tab Building a Profile Profile Settings: Local & Remote Encoders Advanced Local & Remote Options Instance Settings Tab Security Settings Connections Contact Closures Switchboard Server Alternate Modes Advanced Instance Settings Auxiliary Serial Switchboard Server Advanced Instance Settings Under Alternate Modes BRIC Normal Settings HTTP Settings...
  • Page 5 VI. Global Settings and Network Manager Global Settings CrossLock VPN Settings AES67 System Settings Advanced Global Settings Advanced CrossLock VPN Settings Network Manager Tab Ethernet Port Settings Network Locations WLAN Adapter 3G/4G Connections Advanced Ethernet Port Settings VII. AES67 Connections Setting Up for AES67 Clocking Instances...
  • Page 6 Outputs VIII. Making CrossLock Connections How CrossLock Works: A Brief Overview Multiple Network Setup IX. Making Connections Via Switchboard X. Making Manual Connections Creating New Remotes Backup Remote Connecting And Disconnecting Special Notes for Manual CrossLock Connections XI. Setting Up Your Switchboard Account Logging in and Setting up Switchboard Creating Users Contact Lists...
  • Page 7 XII. Operating MultiRack In A 24/7 Environment Always Connect To Backup Remote XIII. POTS Connections Pots Codec Setup for MultiRack Compatibility Using MultiRack With POTS Rate Drop vs. Retrain Troubleshooting A POTS Connection XIV. About The Algorithms HE-AAC HE-AACv2 Linear PCM* FLAC* G.722 Opus...
  • Page 8 MultiRack Rack Receives the Call Using CrossLock with Multistream Connections XVI. IP Multicast Multicast Profiles Setting Up a Multicast Remote Time-To-Live Changing Port Numbers for Multicast XVII. Streaming Server Function Decoding a Stream Simultaneously Connecting MultiRacks And Streaming XVIII. Making EBU3326/SIP Connections More About EBU3326 EBU3326 in MultiRack EBU3326/SIP Modes...
  • Page 9 Making Registered SIP Calls Advanced EBU3326/SIP Topics SIP Troubleshooting Outgoing Call Issues Incoming Call Issues Solutions Stunning Success Fix of Last Resort XIX. License & Warranty Disclosures for MultiRack License Warranty XX. Switchboard Traversal Server Disclaimer Traversal Server Disclaimer XXI. Conformity And Regulatory Information Suppliers’...
  • Page 10 APPENDIX B: IP Compatibility APPENDIX C: Unidirectional Networks Standard RTP Settings Decode Side Settings Only Encode Side Settings Only Full-Time Or Triggered Connections APPENDIX D: Information For IT Managers 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

    MultiRack incorporates five separate codec “instances” in a single hardware box. The instances present as five separate codec products that each have all the features of individual Comrex codecs. The codec instances share the dual Ethernet interfaces, along with any USB Network devices that are attached. They also share a common web- based control page, although separate control pages are also available.

  • Page 13: Transmission Modes And Delay

    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: Additional Features

    AoIP routing systems will accommodate. HTML 5 Previous firmware versions for Comrex codecs provided a web-based control page powered by Adobe Flash. As Flash has lessened in popularity and impedes operation on many mobile browsers, MultiRack (and older Comrex...

  • Page 15: Diagrams And Installation

    MULTIRACK DIAGRAMS AND INSTALLATION 3 & 4 5 & 6 FIgure 1 reAr pAnel dIAgrAm And descrIptIons AC Input - An IEC connector for the main power. MultiRack works on worldwide AC power at 110-240 VAC 50-60 Hz, 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 16: Front Panel Diagram And Descriptions

    FIgure 2 Front pAnel dIAgrAm And descrIptIons Contact Closure Input/Output (Instance #1) - Provides four sets of contact closure inputs and outputs, which can be used to initiate outbound connections, or send signals to the far end of the link to trigger remote control gear (e.g., automation equipment).

  • Page 17: Mono Vs. Stereo

    mono Vs. stereo Regardless of whether audio input is configured as analog, AES3, or AES67, MultiRack uses its left channel input only for encoder Mono Modes. The right channel is omitted. Output audio is available at both the left and right outputs in decoder Mono Modes.

  • Page 18: Pinouts - Serial Port (Instance 1)

    Instance #2 Instance #3 Instance #4 Instance #5 CC in #1 IDI0 IDI4 IDI8 IDI12 CC in #2 IDI1 IDI5 IDI9 IDI13 CC in #3 IDI2 IDI6 IDI10 IDI14 CC in #4 IDI3 IDI7 ISI11 IDI15 CC out #1 IDO1 IDO5 IDO9 IDO13...
  • Page 19 External Serial Port MultiRack Instance Because USB-Serial converters are designed to connect to computers, these adapters break out to DTE-style (male) RS232 pinning. To attach to a PC or other DTE style ports, they will require null-modem adapters on each of the four RS232 DB9 connectors.

  • Page 20: Quick Start - Connections With Multirack

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

  • Page 21: About Multirack Instances

    ABOUT MULTIRACK INSTANCES The web-based user interface opens to the control page for instance #1 on MultiRack. Instance #1 is unique because it’s the only codec instance capable of using the analog/AES3 audio I/O ports. The default for instance #1 is not to use these ports, but to use the AES67 Audio over Ethernet function instead.

  • Page 22: Receiving Incoming Connections

    FIGURE 5 SWITCHBOARD CONNECTIONS ICONS RECEIVING INCOMING CONNECTIONS By default, MultiRack is set to automatically answer incoming calls, whether or not Switchboard is used to make them. Incoming calls will appear in your connections list while they are active. They can be disconnected locally by highlighting them and clicking “Disconnect”.

  • Page 23: Using The Device Manager Program

    As shown in Figure 7, running the Device Manager and clicking the “Scan” button will produce a list of all Comrex devices found on the LAN. Device Manager will attempt to log in to each device using the default password. If the default password has changed, Device Manager will prompt for the password to MultiRack after the scan.
  • Page 24 FIgure 8 toolboX logIn Generally, it is recommended to configure the Ethernet port of an ACCESS MultiRack for a static IP. This will facilitate access to the Web-based Interface with a browser and allow for easier configuration of routers or firewalls (if necessary).

  • Page 25: Updating Firmware Using Device Manager

    FIgure 9 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 10 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 10).

  • Page 26: Network Recovery Mode

    FIgure 10 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 27 FIgure 11 network recoVery mode...

  • Page 28: Configuring Multirack

    2) The console interface does not require a login procedure. LOGIN Upon connection to the MultiRack, a login screen will appear, Figure 12. Any username can be chosen and used with the default password: comrex. This will access the Main User Interface display. FIgure 12 web InterFAce logIn CONTROLLING MULTIRACK INSTANCES MultiRack consists of five “instances”...

  • Page 29: Instance Pages And Global Settings

    the five control pages, and selection can be made on-the-fly between them. It is only required to log into the aggregated page once, and each instance may be selected without added security logins. The aggregated page defaults to show the instance #1 options. The currently selected instance can be changed by selecting the menu (hamburger) button in the upper left corner of the page.

  • Page 30: 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 Name and Status information of a remote Comrex codec when it has initiated a connection to the MultiRack.

  • Page 31: Performance Tab

    FIgure 15 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 32: Codec Channel Field

    FIgure 17 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 17, which illustrates a spread of jitter values (referenced to the current play out pointer) over the last second.

  • Page 33: Packet Loss Graph

    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 34: 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 Automatic Delay Mode settings. But during connections on unusual networks, these sliders are designed to quickly adjust the current delay settings.

  • Page 35: Profile Manager Tab

    provide stability. These “zones” scale, increase and decrease in size based on the history of jitter experienced by CrossLock on the network. In “Auto Delay” mode, the dark dot signifies the “Current Delay”, which is the best compromise value calculated by the system to balance stability and delay. By changing the “Automatic Delay Mode” switch to manual, the “Target Delay”...

  • Page 36: Building A Profile

    Next is the Channel option (3 in Figure 24), which allows for selecting between a standard Comrex IP connection (BRIC normal) or one of the other connection modes offered by MultiRack. Note that when using the CrossLock reliability layer, BRIC Normal mode is chosen here, as this is the protocol that runs with the CrossLock VPN.

  • Page 37: Advanced Local & Remote Options

    These advanced options are a means of overriding the 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 38 Retransmit Squelch Max - The longest period of data loss during which the squelch function is active. Default is two seconds. During the squelch period, the buffer manager ignored the relative jitter experienced and does not adjust 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.

  • Page 39: Instance Settings Tab

    Congestion Avoidance - Enabling this option allows the encoder to dynamically change the number of frames per packet sent, thereby reducing total data requirements. In addition, in most encode modes, enabling congestion avoidance provides the system a license to step down to a lower encode data rate if desired. This will happen automatically and with no audio interruption.

  • Page 40: Security Settings

    Remote Control Password - This allows for a defined password for the web GUI and firmware updates. The default password is comrex (lowercase). The remote control and firmware updating functionality can be disabled completely by disabling the Remote Control option. Although this option appears in the Instance config page, it is global in scope and will change the password for each instance.

  • Page 41: Switchboard Server

    Server Address - The Internet URL of your Switchboard server. Default is the server maintained free of charge by Comrex. If you are running a custom Switchboard server, put the URL or IP address here. Secure - Enables Switchboard to operate over a secure channel. This option is the default and is recommended when using the Comrex Switchboard server.

  • Page 42: Advanced Instance Settings

    9002, instance #3 to 9003 and so on. Legacy Comrex codecs all use port 9000 as their standard incoming connection port. With no port designation on an outgoing call, 9000 will be used. An important element of MultiRack is that incoming calls to instances other than #1 must dial specifically to the new port number in order to connect to the correct instance.

  • Page 43: Http Settings

    HTTP SETTINGS HTTP settings involve the built-in Shoutcast/Icecast-compatible streaming server built into MultiRack. Accept Incoming Connections - Users can set MultiRack to listen for and automatically answer any HTTP incoming requests. This option is set to No by default. IP Port - This option defines the incoming TCP port—the number to be used for incoming HTTP connections. The default is TCP 8000 for instance #1 for legacy purposes.

  • Page 44: Tcp Settings

    VIP QC Password - For legacy purposes with the VIP QC app, which has been deprecated. RTP IP Port - The port used for audio transfer during EBU3326/SIP mode. Since this port info is transferred during the negotiation process, it can be changed without breaking compatibility. Note: RTSP data is always sent and received on the port one number higher than this.

  • Page 45: Miscellaneous

    MISCELLANEOUS Meter Demo Mode - This setting will put the front panel LED meters into a demonstration mode. This setting is set to No by default.

  • Page 46: Global Settings And Network Manager

    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.

  • Page 47: Aes67 System Settings

    If you are not using Switchboard and need to change the CrossLock UDP port, there will be special entries required on the calling codec. See the Comrex Tech Note “Non-Standard CrossLock Ports and non-Switchboard Connections” on www.comrex.com for more information.

  • Page 48: Network Manager Tab

    Ports or connected 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 MultiRack on a managed LAN, Comrex strongly recommends that users consult their IT manager in environments where these concerns are present.

  • Page 49: Ethernet Port Settings

    FIgure 26 network mAnAger mAIn screen The primary ethernet port for MultiRack is configured for DHCP by default. In this configuration, MultiRack will be assigned an IP address from a pool of available IP addresses from the network router upon booting. If MultiRack is connected to the Internet, it should display connection information for the Ethernet Port, including IP and DNS server addresses.

  • Page 50: Network Locations

    IP Type to open a drop down selection screen. This will give users the option to change the “Default” Network Location to Static IP, DHCP, or Gateway IP types as shown in Figure 28. FIgure 28 ethernet port deFAult settIngs NETWORK LOCATIONS While the “Default”...

  • Page 51: 3G/4G Connections

    FIgure 30 wlAn AdApter settIngs 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 30).

  • Page 52: Advanced Ethernet Port Settings

    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 MultiRack, and you will then have to use the Device Manager program‘s Network Recovery Mode (discussed on...

  • Page 53: Aes67 Connections

    AES67 CONNECTIONS VII. 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 (via 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 54: Setting Up For Aes67

    • Instance #1 on MultiRack 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 MultiRack are entirely disabled when instance #1 is in AES67 mode, including outputs. SETTING UP FOR AES67 AES67 settings are located in the Global Settings section in the Main Menu.

  • Page 55: Instances

    MultiRack input) audio channel to be 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 MultiRack input stream is active, choose the instance input setting in the AES67 options, and select “Source”.

  • Page 56: Setting Input Delay

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

  • Page 57: Aes67 Output

    AES67 OUTPUT On MultiRack, an AES67 output stream is automatically created for each instance. This stream has the following parameters: 2 channel • 48 kHz sampling • 1 ms 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 58 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. Payload Type - This is a value sent in outgoing stream advertisements. AES67 default is 98. If your AoIP system has special requirements, it can be changed here.

  • Page 59: Making Crosslock Connections

    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 MultiRack and ACCESS Codec connections.

  • Page 60: Multiple Network Setup

    As shown in Figure 38, BRIC Normal connections happen over the CrossLock VPN Layer. The CrossLock connection between the Comrex hardware happens over a single port (9001), but the BRIC Normal connections take place virtually on their usual legacy ports within that VPN. The system will show these virtual connections happening on ports 9000, 9002 and 9003 (these are the BRIC Normal ports)—however, the only actual connection between...
  • Page 61 Finally, CrossLock can be configured to use one network only when the primary network fails. This is called “HotSwap” mode and is described in a later section. As long as an incoming CrossLock call is possible on the primary network attached to a codec, the call may be initiated from the remote end of the connection.

  • Page 62: Making Connections Via Switchboard

    MAKING CONNECTIONS VIA SWITCHBOARD ON MULTIRACK This section describes the procedure of making and receiving connection on MultiRack via the Comrex Switchboard server. This is the easiest way, but not the only way to make MultiRack connections. Before connections are made this way, you must set up and configure a Switchboard account as described in Section XI.
  • Page 63 Once your Switchboard peers are configured, connecting to one is simple: 1. Select the desired Switchboard peer. 2. Make sure the “gear” icon is green. 3. Click “Connect” in the upper-right corner. Switchboard connections can be ended on either end of the link, by choosing the active connection in the list and clicking “Disconnect”.

  • Page 64: Making Manual Connections

    MAKING MANUAL CONNECTIONS creAtIng new remotes When connections are added to the list manually, we call them “remote entries,” or “remotes” for short. To create a new remote connection, click on the “Plus Sign” (+) on the right of the screen (1 in Figure to Add A New Remote Connection.

  • Page 65: Backup Remote

    FIgure 41 proFIle mAnAger tAb bAckup remote MultiRack features an ability to have an automatic backup to a designated remote connection. A specific backup connection (for when the primary fails) is designated when a new remote is created. As shown in Figure 42, selecting the backup option opens a menu allowing selection of other outgoing remotes that have been created.

  • Page 66: Connecting And Disconnecting

    In the special circumstance where the default CrossLock port of UDP9001 cannot be used (e.g. several MultiRack codecs sharing a single IP address), then manual CrossLock connections get extra complex. For more information on these settings, refer to the Technote “Making CrossLock connections on non-standard Ports” on www.comrex.com.

  • Page 67: Setting Up Your Switchboard Account

    SETTING UP YOUR SWITCHBOARD ACCOUNT 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 MultiRack unit.

  • Page 68: Creating Users

    FIgure 45 swItchboArd unIt lIst 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 46). This allows for the creation of accounts for users that can later be deleted.

  • Page 69: Following Contact Lists

    FIgure 47 contAct lIst By default, a master Contact List is created that contains all codecs in an account. Every codec in the fleet uses the master list by default. For users uninterested in segregating codes on their account, the default configuration will work fine.

  • Page 70: Shares

    FIgure 49 unIt screen To follow a Contact List on a codec, first click on the “Details” button for that codec on the main screen in Switchboard (Figure 48). Next, press the “Change” button near the middle of the following screen (Figure 49).
  • Page 71 FIgure 51 unIt shArIng tAb FIgure 52 shAre A deVIce To create a Share, click the Sharing tab and then select “Add New Share” (Figure 51). The following screen then allows users to choose which codec(s) they want to include in a Share (Figure 52).

  • Page 72: Managing Multiple Contact Lists

    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 55).

  • Page 73: Bulk Actions For Contact Lists

    FIgure 56 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 56). To view and/or connect to the unit(s) within a list, select the list and press the Open Folder button on the upper right.
  • Page 74 FIgure 58 bulk ActIons To do this, press the Bulk Action button in the bottom right corner of the Contact List tab (Figure 58). The three steps to create a Bulk Action are: 1. Choose the type of action to perform. 2.
  • Page 75 FIgure 60 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). Note: Bulk Actions can ONLY be performed on ENTIRE Contact Lists.

  • Page 76: Switchboard Theory And Concepts

    Switchboard Theory and Concepts Switchboard is useful because it’s not always simple to connect two devices, which are essentially “peers”, over the Internet. There are two major reasons for this. First, to initiate a stream to a device over the Internet requires knowing its IP address.
  • Page 77 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 78 can easily imagine the complications of obtaining or managing port forwarding on the LAN when arriving at a new remote venue. This would likely encounter a large amount of resistance or confusion on the part of local IT staff. In describing NAT routing, it’s important to understand the concept of ports. These are numbers, like the source and destination IP addresses that are attached to each packet.
  • Page 79 FIgure 64 bIdIrectIonAl communIcAtIon Switchboard aids in breaking through these different types of routers for incoming calls. Because it is in constant contact with all subscribed codecs, it can send and receive test patterns to determine whether one or more NAT routers exist on a link and what type they are.

  • Page 80: Operating Multirack In A 24/7 Environment

    OPERATING MULTIRACK IN A 24/7 ENVIRONMENT XII. MultiRack 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), MultiRack transfers all its audio data via the UDP 9000 protocol.

  • Page 81: Backup Remote

    FIgure 65 AlwAys connect to settIng bAckup remote MultiRack 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 82 Additionally, there is a box in the Change Remote Settings tab labelled 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 83: Pots Connections

    POTS CONNECTIONS XIII. MultiRack 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 where MultiRack is used) and the call is placed directly from one MultiRack (or legacy codec) to the other.

  • Page 84: Troubleshooting A Pots Connection

    Rate Drop and Retrain controls are similar in function to those provided on POTS codecs. MultiRack will initially connect at the best data rate supported by the telephone line, and will display this rate on the Connections Tab page. FIgure 67 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.
  • Page 85 • 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 86: About The Algorithms

    ABOUT THE ALGORITHMS XIV. When building profiles for MultiRack 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 87: 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 88: Algorithm Codec Profiles Chart

    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 128 kb/s 69 ms 20 kHz...

  • Page 89: Multistreaming

    MULTISTREAMING MultiRack supports the ability to run one encoder per instance, but this single encoder stream may be sent to up to three destinations simultaneously. This capability is referred to as a Multistream, as the encoder creates a separate but identical outgoing stream to each decoder. (Note: A User’s Internet connection must be able to support these streams.) For example, if an encoder runs at 35 kb/s network utilization, sending to two locations will require 70 kb/s upload speed from the network.

  • Page 90: Multistreaming Arrangements

    CrossLock functionality in Multistreaming has been introduced with MultiRack. Previous Comrex Access Racks did not support CrossLock VPN when performing a Multistream. With the introduction of MultiRack, the added...

  • Page 91: Ip Multicast

    IP MULTICAST XVI. IP Multicast is an efficient way of delivering MultiRack 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. Performing an IP Multicast requires the use of an IP Multicast-capable network.

  • Page 92: Setting Up A Multicast Remote

    The important settings for Multicast are: • Sender/Receiver - Determines whether this particular MultiRack 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 93: Streaming Server Function

    STREAMING SERVER FUNCTION XVII. MultiRack 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 94: Decoding A Stream

    And streAmIng MultiRack can stream while connected to another Comrex codec in BRIC Normal mode. If the BRIC connection is using an AAC algorithm supported by players, then when a stream is requested it will be delivered using the same encoder as the BRIC connection, regardless of the HTTP settings.

  • Page 95: Making Ebu3326/Sip Connections

    MAKING EBU3326/SIP COMPATIBLE CONNECTIONS XVIII. 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 96: 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 97 • The password on the SIP account. Figure 74 shows how this information can be applied—by enabling the Use SIP Proxy option under EBU 3326/SIP on the Systems Settings tab. FIgure 74 ebu3326/sIp settIngs Once this information is correctly entered, a new field appears in the “Registration Status” box located on the Connections tab (Figure 75).

  • Page 98: 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: •...

  • Page 99: Sip Troubleshooting

    IP address from the incoming data and return a channel to that address. This is the default method Comrex devices use to create and maintain a connection. But SIP includes a separate “forward address” or “return address” field, and requires that a codec negotiating a call send to that address only.

  • Page 100: Solutions

    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 101: License & Warranty Disclosures For Multirack

    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 102: 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 Road, Devens MA 01434 USA. For return authorization, contact Comrex at 800-237- 1776 or 978-784-1776 or email techies@comrex.com.
  • Page 103 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 104: 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 105: Conformity And Regulatory Information

    Date of Issue: January 23, 2006 Equipment: Comrex ACCESS MultiRack Comrex Corporation, located at 19 Pine Road, Devens, MA in the United States of America hereby certifies that the Comrex ACCESS MultiRack 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 106: Ec Declaration Of Conformity For R&Tte Directive

    For r&tte dIrectIVe Manufacturer’s Name: Comrex Corporation Manufacturer’s Address: 19 Pine Road Devens, MA 01434 hereby declare on our sole responsibility that the product: Comrex ACCESS MultiRack 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).

  • Page 107: Canada Regulatory Information

    U.S. telephone company. Telephone line connections to the Comrex ACCESS MultiRack 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 108: Appendix A: Hotswap

    For 24/7 operation, this data will total less than 0.5 GB for a typical month of usage, assuming no 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...
  • Page 109 assumes no liability for data overage charges, even in the event of software bugs or any other failure of hardware or software. It is entirely the responsibility of the user to monitor any metered data usage. setup Setup for HotSwap is done entirely on the end of the link that has dual networks connected. On the MultiRack, the best way to set up HotSwap is via the Network Manager page, accessible via the web-based interface.
  • Page 110 Select “Save Settings”, then click “Close” or press ESC to exit Network Manager. Reselect the Main Menu and navigate to the Global Settings page. Under CrossLock VPN, locate the entry labelled “Redundant Transmission” (Figure 79). Change this from the default “Off” to “On”, and then click “Apply Changes”. FIgure 79 crosslock redundAnt trAnsmIssIon Finally, set one of the contact closures to sound an alert when the HotSwap function is engaged.
  • Page 111 FIgure 81 hotswAp cc IndIcAtor...
  • Page 112 APPENDIX B - IP COMPATIBILITY The MultiRack is capable of encoding and decoding a choice of three different types of non-MultiRack streams: Standard RTP, Luci Live and Zephyr Xstream. The choice is exclusive— i.e., you must set the MultiRack 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 113 • Outgoing Connections - Build a profile using the Profile Manager on the MultiRack 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 MultiRack. 3.
  • Page 114 AppendIX c - multIrAck on unIdIrectIonAl networks Under most circumstances, MultiRack 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 115 Comrex provides Device Manager, a Windows- or MAC-compatible application, on the included CD or available on our website at www.comrex.com, to perform this function on the local computer. Once the unit is powered on your MultiRack, you have five minutes before this function is disabled.
  • Page 116 Service Destination 0.comrex.pool.ntp.org:123 (UDP) Switchboard switchboard.comrex.com:8090, switchboard.comrex.com:8081 (secondary) (TCP) STUN stun.comrex.com:3478 (UDP) DNS Lookup DNS Server:53 (TCP and UDP)

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