Model 372A Intercom Beltpack User Guide Issue 1, April 2019 This User Guide is applicable for serial numbers M372A-00151 and later with application firmware 1.1 and later Copyright © 2019 by Studio Technologies, Inc., all rights reserved www.studio-tech.
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MODEL 372A INTERCOM BELTPACK Table of Contents Revision History ........................................................... 4 Introduction ................................................................... 5 Getting Started ............................................................. 8 Operation ...................................................................... 13 Technical Notes ............................................................ 17 Specifications ............................................
MODEL 372A INTERCOM BELTPACK Revision History Issue 1, April 2019: • Initial release. Issue 1, April 2019 Page 4 Model 372A User Guide Studio Technologies, Inc.
MODEL 372A INTERCOM BELTPACK Introduction The Model 372A Intercom Beltpack is a highly compact user-worn device that combines a single channel of talk and two channels of listen. The unit begins with the features offered by traditional analog partyline (PL) intercom user devices and adds a range of new capabilities, along with the advanced performance and flexibility that Dante® audio-over-Ethernet provides.
MODEL 372A INTERCOM BELTPACK A broadcast or intercom-style headset with a dynamic or electret (DC-powered) microphone can be interfaced with the Model 372A using a 5-pin XLR connector. The Model 372A also directly supports connection of earbuds or gaming headsets that utilize a 3.5 mm 4-conductor TRRS plug. These moderately priced devices, commonly associated with mobile phones or personal computers, are often of high-quality and may be preferred for some applications.
MODEL 372A INTERCOM BELTPACK level control, and sidetone creation are performed within the digital domain. This provides flexibility, allowing precise control of the audio signals and eliminating the need for the two rotary level controls from having to directly handle analog audio signals. The audio signals destined for the 2-channel headphone output are sent to a highperformance digital-to-analog converter and then on to robust driver circuitry. High signal levels can be provided to a variety of headsets.
MODEL 372A INTERCOM BELTPACK Future Capabilities and Firmware Updating The Model 372A was designed such that its capabilities and performance can be enhanced in the future. A USB connector, located on the unit’s main circuit board (underneath the unit’s cover), allows the application firmware (embedded software) to be updated using a USB flash drive. The Model 372A uses Audinate’s Ultimo™ integrated circuit to implement the Dante interface.
MODEL 372A INTERCOM BELTPACK dual-ear intercom- or broadcast-style headset. The connector is labeled Headset A. Refer to Figure 2 for connection details. The microphone input connections are compatible with most unbalanced dynamic or electret (low-voltage DC-powered) microphones. A balanced dynamic microphone should, in most cases, also function correctly if its signal – (low) is connected to Model 372A’s mic in –/shield connection.
MODEL 372A INTERCOM BELTPACK power and requires only that the appropriate setting in STcontroller be selected. Refer to Figure 3 for a detailed description of the compatible TRRS plug. Figure 3. Headset B connection pinout chart Dante Configuration For audio to pass to and from the Model 372A requires that several Dante-related parameters be configured. These configuration settings will be stored in non-volatile memory within the Model 372A’s circuitry.
MODEL 372A INTERCOM BELTPACK settings or other local actions are used to configure the unit. This makes it imperative that the STcontroller software application be available for use in a personal computer that’s connected to the related LAN. STcontroller is available free of charge on the Studio Technologies’ website (www. studio-tech.com/stcontroller-application/) and is compatible with personal computers running Windows operating systems that are version 7 and later. STcontroller version 2.01.
MODEL 372A INTERCOM BELTPACK When a dynamic microphone is connected to the Model 372A the 42 dB gain setting should be appropriate for many applications. The 36 dB choice may be correct should the connected microphone have a high sensitivity (high output level for a given acoustical input) or an enthusiastic user routinely talks loudly into the microphone. Setting the gain for 48 dB may be helpful in some applications, such as with headsets that have a low microphone output level.
MODEL 372A INTERCOM BELTPACK Talk Button Operation Choices are Push to Talk, Latching, and Push to Talk/Tap to Latch. This configuration section allows selection of how the talk button will function. When the Push to Talk mode is selected the operation is self-explanatory. Only when the talk button is pressed and held will talk audio be sent out the Dante transmitter channel.
MODEL 372A INTERCOM BELTPACK Ethernet and Dante Status LEDs Three status LEDs are located below the etherCON RJ45 receptacle on the Model 372A’s bottom panel. The LINK ACT LED will light green whenever an active connection to a 100 Mb/s Ethernet network has been established. It will flash in response to Ethernet data packet activity. The SYS and SYNC LEDs display the operating status of the Dante interface and associated network.
MODEL 372A INTERCOM BELTPACK Push to Talk When the button has been configured for the Push to Talk mode how it functions is pretty self-explanatory. Press and hold the button when headset microphone audio is to be sent out the Dante audio output (transmitter) channel. The button’s green LED will light to indicate that the output is active. The button will not be lit when the function is not active.
MODEL 372A INTERCOM BELTPACK Digital filters within the Model 372A’s processor integrated circuit help to ensure that false call detection won’t take place. Digital filtering is also performed on the microphone audio output signals as well as the audio input (Dante receiver) signals before they are sent to the headphone outputs. This prevents users with extended high-frequency sensitivity, such as hosts and guests associated with dog shows, from receiving undesirable audio content.
MODEL 372A INTERCOM BELTPACK Technical Notes IP Address Assignment By default, the Model 372A’s Ethernet interface will attempt to automatically obtain an IP address and associated settings using the DHCP (Dynamic Host Configuration Protocol). If a DHCP server is not detected an IP address will automatically be assigned using the link-local protocol. This protocol is known in the Microsoft® world as Automatic Private IP Addressing (APIPA). It is also sometimes referred to as auto-IP.
MODEL 372A INTERCOM BELTPACK (EEE) support on all Ethernet switch ports that are associated with Dante devices. Some implementations of EEE can incorrectly interpret that a connected Dante device is not present and prevent proper operation. Application Firmware Version Display There are two ways in which the version number of the Model 372A’s application firmware (embedded software) can be identified. One requires only the Model 372A unit and involves a button-press sequence performed upon power up.
MODEL 372A INTERCOM BELTPACK name of the zip file itself will include the file’s version number. For example, a file named M372Av1r2MCU.zip would indicate that version 1.2 of the application firmware (M372A.bin) is contained within this zip file. Once a correctly prepared USB flash drive is inserted into the USB interface, located under the cover of the Model 372A’s main circuit board, the unit must be powered off and again powered on.
MODEL 372A INTERCOM BELTPACK The STcontroller software application can also be used to identify Ultimo’s firmware version. (Use the Version selection under the Device tab.) The Ultimo firmware can be updated by way of the Model 372A’s Ethernet connection. The latest Ultimo firmware file is available on the Studio Technologies’ website. The Dante Firmware Update Manager (FUM) application program has traditionally been used to install the Ultimo firmware.
MODEL 372A INTERCOM BELTPACK Specifications Power Source: Power-over-Ethernet (PoE): class 1 (very low power, ≤3.84 watts) per IEEE® 802.
MODEL 372A INTERCOM BELTPACK Appendix A STcontroller default Model 372A configuration values: Microphone Input – Electret Power: Off Microphone Input – Gain: 36 dB Headphone Output – Channel 1 Input Routes to: Left Headphone Output – Channel 2 Input Routes to: Right Headphone Output – Sidetone Level: Medium Button Operation – Talk: Push to Talk/Tap to Latch Model 372A User Guide Studio Technologies, Inc.
