The GPIO model is composed of 6 DA15 GPIO ports. Each port contains 5 GPIs (opto isolated inputs) and 5 GPOs (solid state relays). Each port is capable of driving a combined current of 100mA . Each GPI pin should be limited to 20mA of current.

Power to the xNode2 is either with an IEC-C13 or a PoE+ connected RJ45 at the top network connection.

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

VDC	External Series Resistor
5	0
6	0
12	680 @ ¼ watt
24	1.8k @ ½ watt
48	3.9 k @ 1 watt

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

GPIO configuration consist of

Name: A useful title that will be ingested by Pathfinder and used as reference to what is wired to the port.
Channel: This text field is used to configure the GPIO port
Input pins : status indicator of the 5 input pins
Output pins : status indicator of the 5 output pins
- TEST switch: The test switch, when enabled, allows for toggling the GPO pins for the purpose of testing your connections.

Three possible configurations can be applied to the channel field of each port.

Port routing - The GPI activity on a designated port will trigger the GPO pins of the port being configured. In other words, routing GPI triggers to GPO triggers. To configure in this manner requires defining the IP address of the device which has the GPI triggers followed by /port number (i.e. 10.216.0.121/5 equates to port 5 of device at address 10.216.0.121)

Channel assignment - The GPIO port will follow the logic as defined by a control surface. Axia control surfaces have predefined logic for a source loaded to a fader. Tables describing the predefined logic can be found in Appendix A: GPIO Tables and GPIO Circuits. The logic states are shared on the network through the use of the unique channel number for a source. To configure the port requires the manually entering the channel number of the source or using the channel picker to pick a source from the advertised network.

Blank or external - Pathfinder can use the port activity exclusively through the Livewire protocol. No configuration to the port is required for Pathfinder to us the port. Configuration becomes part of Pathfinder.

Above demonstrates a configuration where the first port has a configuration of routing the GPI activity of port 5 on device at 10.216.0.121. So the transmitter site is wired to GPI pins of port 5 and those triggers will appear as GPOs on this device in the studio facility. Ports 2 - 4 are wired to Axia GPIO panels and give remote control of those mics to the guests. From the GPO states shown (ref to Appendix A), it appears that Guest 1 is ON, while Guest 2 and 3 are in the OFF state. Port 5 and 6 have no configuration and are used by Pathfinder to trigger activities through Pathfinder.

Appendix B: xNode2 Specifications