Model 44D Audio Interface Dante® to and from Analog Audio User Guide Issue 3, August 2018 This User Guide is applicable for serial numbers M44D-01151 and later with application firmware 2.2 and later and Dante firmware 2.0.0 (Ultimo 3.10.1.12) and later Also applicable to units with serial numbers M44D-00151 to 00250; see Appendix A for details Copyright © 2018 by Studio Technologies, Inc., all rights reserved www.studio-tech.
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Table of Contents Revision History ............................................................ 4 Introduction ................................................................... 5 Getting Started .............................................................. 9 Configuration ................................................................ 14 Operation ...................................................................... 17 Technical Notes .............................................................
Revision History Issue 3, August 2018: 1. Documents change of tone frequencies from 1 kHz and 18 kHz to 18 kHz and 20 kHz. Issue 2, November 2017: 1. Documents addition of operating mode configuration (audio interface and tone generator). Issue 1, September 2016: 1. Initial release. Issue 3, August 2018 Page 4 Model 44D User Guide Studio Technologies, Inc.
Introduction The Model 44D Audio Interface provides a simple yet high-performance means of interfacing two channels of analog line-level audio to and from applications that utilize Dante® audio-over-Ethernet media networking technology. Two Model 44D units can also provide one-to-one signal paths, two in each direction, over a standard local area network (LAN). In addition, the unit supports transport of status signals or contact closures between Model 44D units and other compatible products.
performance, strong interoperability, and wide adoption by a large number of equipment manufacturers. The Model 44D is a general-purpose “tool” that helps to expand Dante’s capabilities to facilities and equipment that primarily supports signals in the analog domain. Careful attention to circuit design and component selection ensures that excellent audio quality is maintained.
The Model 44D’s tone generator mode enables the unit to create 18 kHz and 20 kHz analog and digital sine-wave audio signals. The 18 kHz tone is provided as a resource when supporting remoteproduction (REMI) applications that use the Studio Technologies’ Model 5422 Dante Intercom Audio Engine. The tone can be used by a matrix intercom system to facilitate creation of voice-with-tone interruptible foldback (IFB) signals.
The GPI and GPO functions can be especially useful in party-line intercom applications where call-light signals are utilized. Contact closures on matrix intercom systems can be “repeated” by Model 44D units that are located anywhere within the associated local area network (LAN). The Model 44D is also directly compatible with the calllight signal support provided by the Studio Technologies’ Model 45DC and Model 45DR Intercom Interface units.
would be for the 20 kHz tone to be used to serve as an activation signal for contact closures. Using Dante subscriptions (routes), the intercom channel from the matrix interface would be connected to additional Model 44D units. When those units receive the 20 kHz tone signal they would enable their associated GPO contact closure. Both the 18 kHz and 20 kHz tones are precise in terms of frequency and level accuracy, as well as being very low in harmonic distortion.
line outputs will be made using 3-pin male and female XLR connectors. An Ethernet data connection will be made using either a standard RJ45 patch cable or an etherCON protected RJ45 plug. A 4-pin XLR connector allows the connection of an external source of 12 volts DC. Interfacing with the GPI, GPO, and auxiliary DC output functions can be made using a 9-pin female D-subminiature (DE-9F) connector.
front panel without interference. To allow vertical clearance in the associated rack, remove the four “bump on” protectors from the bottom of the chassis. They are removed by using the fingers to rotate them counterclockwise; no tool is required. It’s probably a good idea to carefully protect and store the standard front panel, along with the “bump on” protectors, for possible later use. Mounting a Model 44D to a dual-unit rackmount panel follows the same procedure but will apply to two units.
As previously discussed in this guide, an Ethernet connection that provides Powerover-Ethernet (PoE) can serve as the Model 44D’s power source. Alternately, an external 12 volt DC source can be connected. For redundancy, both PoE and an external 12 volt DC source can be connected at the same time. If both PoE and an external 12 volt DC source are connected, power will be drawn only from the PoE supply.
anything to pin 3. Do not short pins 3 to pin 1 on the Model 44D’s line output connectors as it will stress the output circuitry. General Purpose Inputs (GPI) The Model 44D provides two general-purpose input functions that are referred to as GPI 1 and GPI 2. These functions allow transport of the status of relay contacts or open-collector logic signals. The Model 44D’s GPI inputs use logic circuitry, “pulled up” to 3.
current of 400 milliamperes and a maximum of 60 volts DC or AC. They are not intended for direct connection to AC mains (high-voltage AC signals.). Pins on a 9-pin female D-subminiature connector (DE-9F), located on the Model 44D’s back panel, allow interfacing with the GPO connections. Two connections are provided for each GPO, pins 1 and 6 for GPO 1 and pins 2 and 7 for GPO 2. Refer to Figure 3 for connection details.
to –20 dBFS in the digital domain. While in Europe (EBU) it would be typical in modern installations for 0 dBu (analog) to be equal to –18 dBFS (digital). But SW1 can be used as a coarse level adjustment function if necessary. In a SMPTE-compliant installation (+4 dBu = –20 dBFS) setting SW1 to its on (up) position will provide a 6 dB increase in input sensitivity. This could be useful if the average level of the signal connected to the line inputs was a little low.
SW3 – 10 kHz Low-Pass Filter ON 1 2 3 4 ON 1 2 3 4 Disabled SW4 – Operating Mode ON 1 2 3 4 ON Enabled Figure 6. 10 kHz low-pass filter configuration switch Full bandwidth audio signals will past through the Model 44D’s line inputs and line outputs. When SW3 is in its on (up) position the low-pass filters will be enabled. Enabling the low-pass filters can improve the performance and possibly the intelligibility of audio signals that consist mainly of voice content.
integrated circuit limits the number of Dante flows to two. These can either be unicast, multicast, or a combination of the two. The Model 44D has a default Dante device name of ST-M44D followed by a unique suffix. The suffix identifies the specific Model 44D that is being configured. The suffix’s actual alpha and numeric characters relate to the MAC address of the Ultimo integrated circuit that’s present in the specific Model 44D. The two Dante receiver (input) channels have the default names of Ch1 and Ch2.
Upon Model 44D power up the status LEDs will light in various manners. The PoE, Dante, and Ethernet status LEDs, located on the back panel, will light in various ways. On the front panel the input power, GPO status, and audio level meter LEDs will light in a sequence. Once the test sequence has completed the two columns of level meter LEDs associated with the line outputs will momentarily display the version number of the unit’s application firmware (embedded software).
presented to the line inputs should match the Model 44D’s configuration. If the nominal input level is configured for –20 dBFS this will equate to a nominal analog input level of +4 dBu. If the nominal input level is configured for –18 dBFS this will equate to a nominal input level of 0 dBu. As such, if the nominal level of the Dante output (transmitter) channels is 6 dB different than expected, either high or low, a user should confirm that the Model 44D’s input configuration has been set correctly.
General The meters are organized into two groups with one group representing the two line inputs and the second group represent-ing the two line outputs. The two meters associated with the line inputs are calibrated in reference to the configuration of the nominal level of the line inputs. When configured for +4 dBu nominal a meter’s 0 LED lighting will indicate that an analog signal with a level of +4 dBu is present on the associated line input.
GPI/GPO Tone Generator Whether or not the general-purpose inputs (GPI) and general-purpose outputs (GPO) functions are implemented will depend on the needs of the specific application. If the appropriate connections are made using the 9-pin D-subminiature connector either or both functions can be utilized. No useraction is required for the functions to be active. There is no user indication when a GPI input has been activated.
Technical Notes IP Address Assignment By default the Model 44D’s Ethernet interface will attempt to automatically obtain an IP address and associated settings using 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 (PIPPA).
version number is displayed. This is useful when working with factory personnel on application support and troubleshooting situations. The five LEDs associated with the line output channel 1 meter are used to display the major release number with a range of 1 through 5. The five LEDs associated with the line output channel 2 meter are used to display the release sub-number which ranges from 1 through 5.
2. Remove the cover from the Model 44D’s enclosure. Begin by removing the four 5/64 hex head screws and internal tooth lock washers, two per side. Be certain to save the screws and lock washers so that re-assembly will be fast and painless. Then carefully remove the cover. Locate the USB connector on the main circuit board. It’s in the rear of the unit, adjacent to the connector used for line output channel 2. Also on the circuit board and adjacent to the USB connector is a very small LED indicator. 3.
Specifications Power Sources: Power-over-Ethernet (PoE): class 1 (very low power, ≤3.84 watts) per IEEE 802.3af External: 10 to 18 volts DC, 0.3 amp maximum at 12 volts DC Line Outputs: 2 Type: analog, electronically balanced, capacitor coupled, intended to drive balanced or unbalanced loads of 2 k ohms or greater.
GPO: 2 Output Type: solid-state relay contact Contact Type: form A (normally open, not shorted), isolated Contact Rating: 400 mA, 60 volts AC/DC, maximum Contact Resistance: 2 ohms, maximum Detection Method: monitors Dante receiver audio path for presence of 20 kHz (±800 Hz) tone at 48 kHz sampling rate, 18.375 kHz (±800 Hz) tone at 44.1 kHz sampling rate. Tones will pass to line outputs unless low-pass filters enabled.
Appendix A: Original vs Updated Model 44D Differences Between Original and Updated Model 44D Units This user guide is intended primarily to support Model 44D units with serial numbers of M44D-01151 and later. These “updated” units incorporate several changes made to the “original” Model 44D units that were first shipped by Studio Technologies. The original units had serial numbers in the range of M44D-00151 through 00250.
GPI, GPO, and Auxiliary DC Output Access to the GPI, GPO, and auxiliary DC output functions on the original units requires the use of an interface cable assembly. One end of the interface cable requires a 10-conductor socket that has two rows of five connectors on 0.1-inch centers. The socket will mate with a 10-pin header that is located on the Model 44D’s circuit board. Access requires that the cover be removed.
10-Pin Header DE-9F Function 1 1 GPO 1-A 3 2 GPO 2-A 5 3 GPI 1 7 4 GPI 2 9 5 Aux DC Out 2 6 GPO 1-B 4 7 GPO 2-B 6 8 COM 8 9 COM 10 --- --- Figure 11. Model 44D GPI/GPO/Aux DC Out 10-pin header and 9-Pin D-sub pinout chart (M44D-00151-00250) Application Firmware Update Procedure The application firmware used for original Model 44D units is compatible with that used in the updated Model 44D units.
