Mixed Signal xNode2

The mixed signal xNode2 has one microphone input, 3 line level stereo analog inputs, 1 AES3 input, 3 line level stereo analog outputs, 1 AES3 output, and 2 GPIO ports (5GPI/5GPO per port).

Power to the model is either with an IEC-C13 or a PoE+ connected RJ45 at the top network connection. The bottom network connection is a non PoE+ interface used for management or streaming redundancy.

The mixed signal xNode2 uses RJ45 connectors for the analog and AES3 audio and an XLR connector for the microphone input. 

The top 4 RJ45 ports are inputs; three analog inputs followed by one AES3 input. The bottom 4 RJ45 ports are outputs; three analog outputs followed by one AES3 output. 

The pinout of an RJ45 port

The XLR-F connector is for a microphone input or mono line input.

The two DA15  female connectors are the GPIO ports. There are 5 input pins and a common return, 5 output relays with a common, a 5 volt power source, and power source ground.

DID YOU KNOW…

The D-sub series of connectors was introduced into the market in 1950s and the computer industry widely used the DB25 for serial and parallel ports. There was a loss of knowledge that the second letter actually refers to the shell size. Because of this, you can commonly find 9-pin serial cables referred to as DB9 when the shell size is actually E (so it should correctly be called a DE9). The same is true for cables in the market for the DA15 will commonly be referred to as a DB15. Also note that the VGA cable connector you are familiar with is a DE15.

The maximum allowed external power supply for logic control is 48 volts DC. The use of current limiting resistor is required for some voltages.

Using external power supplies is a recommended method to avoid ground loops between equipment. If the device being controlled is electrically isolated, than the 5vDC supply can be used, maintaining a 100mA limit on current.

Accessory modules from Telos Alliance use the 5vDC supply to illuminate LED based buttons. So a one-to-one pin connection is all that is needed between any accessory module and a GPIO port.

All the inputs and output on a specific GPIO port are grouped together. The 5 outputs are on 5 separate pins, however, they share the same Common Return connection on pin-7. Similar, the 5 input pins would be pulled to ground to activate them, and they share a common pin for a high-side rail, on pin-10. If more than one remotely -controlled device is to be connected to a single 15-pin GPIO port, the two units must have the same ground potential or ground loops will occur. It is recommended that only one remote device be connected to each GPIO port to assure complete electrical isolation. Appendix A: GPIO Tables and GPIO Circuits has more details on wiring to the ports.

Setup

Chapter Two describes how to assign an IP address to the xNode2. Chapter Three, In-Depth, describes the various pages available in the xNode2. Once you have your inputs inserted, login to the HTML interface and select the I/O link. Give each AoIP Sender a name that describes the audio source. This becomes useful when browsing the network. Assign any gain needed for the source or leave at the default unity gain of 0. Each sender on the network needs a unique channel between 1 and 32767. A common model is to use the last octet of the IP address as a preamble to the channel number. For example, and address of 192.168.2.202 could utilize the channels 2021 - 2025. Figure out a scheme that works for your facility deployment. Define if the stream shall be a Live Stereo or Standard Stereo. Determine if your facility has a common sync for the AES3 equipment or to use the sample rate conversion in the xNode2. Enabling SRC allows for not needing all the AES3 equipment to be in sync. Determine if the microphone connected is a condenser microphone and if so you will need to apply phantom power to the microphone. The mode of the input is assumed to be microphone, but there is the option to switch it to line. Determine an appropriate mic gain that provides suitable audio. Press the Save button and now the xNode2 is streaming AoIP into the network.

The AoIP Receivers portion of the I/O page is similar in that the name field is useful for documenting what is connected to the xNode2 and thus receiving the audio in the AoIP stream. Define any gain values needed for each receiver or leave at the default unity gain. Use the channel picker to browse the network for the desired stream or type it in directly into the channel field if the channel number is known. Press the Save button and now the devices connected to the xNode2 are receiving audio (assuming there is audio in the received audio streams).