GatewayClient gw = new GatewayClient(new ConnectionInfo(ConnectionType.ZIGBEE_UART, "/dev/ttyUSB0"));
...
Device device = gw.getDevice(id);
device.ping().thenAccept( pingResult -> System.out.println(pingResult) );
...

{
	"gatewayApiVersion":"2.0.4",
	"protocolName":"zigbee",
	"protocolVersion":"3",
	"messageType":"zcl_unicast",
	"message":
		{
			"nodeId":"0x1234",
			"endpointId":"0x01",
			"localEndpoint":"0x01",		// optional, will default to 0x01
			"clusterId":"0x0006",
			"responseOptions":"0x02", 	// optional, will default to no response
			"encryption":"0x01", 		// optional, will default to network encryption
			"frameControl":"0x00",		// optional, will default to ZCL General Command, Client-to-Server
			"manufacturerCode":"0x00", 	// optional, will only be read if frameControl requires it
			"transactionNum":"0x00",	// optional, will only be read if responseOptions requires it
			"commandId":"0x00",
			"payload":"0x0001030405" 	// optional, can omit if there's no payload. Otherwise, expect byte(s) in adherence to the zigbee spec
		}
}"directOrIndirect":{"value":[1]}, // byte value: 0 = response received directly from target device, 1 = response received indirectly from target device
  "lastHopLQI":255,					// LQI of last responding hop
  "lastHopRSSI":-13					// RSSI (in dBm) of last responding hop
}

{
	"gatewayApiVersion":"2.0.4",
	"protocolName":"zigbee",
	"protocolVersion":"3",
	"messageType":"zdozcl_unicastbroadcast",
	"message":
		{
			"nodeIdbroadcastAddress":"0x12340xFD",
			"responseOptionsendpoint":"0x020x01",
	// optional, will default to no response
			"transactionNumlocalEndpoint":"0x000x01",		// optional, will onlydefault beto read if responseOptions requires it
0x01
			"commandIdclusterId":"0x00010x0006",
			"payloadradius":"0x00010304050x00" 				// optional, canwill omitdefault ifto there's no payload. Otherwise, expect byte(s) in adherence to the zigbee spec
		}
}

{
	"gatewayApiVersion":"2.0.4",
	"protocolName":"zigbee",
	"protocolVersion":"3",
	"messageType":"zdo_broadcast",
	"message":
		{
			"broadcastAddress":"0xFD",
			"radius":"0x00"				0x00 (max radius)
			"responseOptions":"0x02", 	// optional, will default to no response
			"frameControl":"0x00",		// optional, will default to ZCL General Command, Client-to-Server
			"manufacturerCode":"0x00", 	// optional, will defaultonly tobe 0x00read (maxif radius)
			"responseOptions":"0x02", 	// optional, will default to no response
frameControl requires it
			"transactionNum":"0x00",	// optional, will only be read if responseOptions requires it
			"commandId":"0x00010x00",
			"payload":"0x0001030405" 	// optional, can omit if there's no payload. Otherwise, expect byte(s) in adherence to the zigbee spec
		}
}

{
	"gatewayApiVersion":"2.0.4",
    	"protocolName":"zigbee",
    	"protocolVersion":"3",
    	"messageType":"zclzdo_responseunicast",
 // other valid value is zcl_passthrough_message
    "message":
        {
            "sourceNode":"0xCB13",
            "sourceEndpoint":"0x01",
            "localEndpoint":"0x01",
            "clusterId":"0x0006",
            "encryption":"0x00",
            "frameControl":"0x02",
            "manufacturerCode":"0x0000",
            "transactionNum":"0x7C",
            "commandId":"0x01",
            "payload":"0x01436300"
        }
}

{
    "gatewayApiVersion":"2.0.4",
    "protocolName":"zigbee",
    "protocolVersion":"3",
    "messageType":"zdo_response",
    "message":
        {
            "sourceNode":"0xCB13",
            "transactionNum":"0x7C",
            "commandId":"0x0001",	"message":
		{
			"nodeId":"0x1234",
			"responseOptions":"0x02", 	// optional, will default to no response
			"transactionNum":"0x00",	// optional, will only be read if responseOptions requires it
			"commandId":"0x0001",
			"payload":"0x0001030405" 	// optional, can omit if there's no payload. Otherwise, expect byte(s) in adherence to the zigbee spec
		}
}

GatewayClient gw = new GatewayClient(new ConnectionInfo(ConnectionType.ZIGBEE_UART, "/dev/ttyUSB0"));
...
// This is an example of using the Protocol Passthrough API, with a zigbee message formed as a json string.
// The zigbee message we're forming is a Zone Enroll Response Command (see ZCL Spec Section 8.2.2.3.1)
Device device = gw.getDevice(id);
Optional<Property> protocolProperty = device.getCachedProperty(PropertyNames.PROTOCOL_PROPERTY_NAME);
if (protocolProperty.isPresent()) {
    Property p = protocolProperty.get();
    JsonObject jsonObject = jsonParser.parse(p.getValue()).getAsJsonObject();
    
    ZCLUnicastMessageBuilder builder = new ZCLUnicastMessageBuilder();
    builder.setGatewayAPIVersion(GatewayClient.getApiVersion());
    builder.setProtocolName("zigbee");
    builder.setProtocolVersion(3);
    builder.setNodeID(jsonObject.get(ZigBeeMessageTypeAdapter.NODE_ID_KEY).getAsString());
    builder.setEndpointID(jsonObject.get(ZigBeeMessageTypeAdapter.ENDPOINT_ID_KEY).getAsString());
    builder.setClusterID(IAS_ZONE_CLUSTER_ID);
    builder.setResponseOptions(ZigBee.FrameConstants.RESPONSE_OPTIONS_APS_RESPONSE.toBitmap8());
    builder.setFrameControl(ZigBee.FrameConstants.FRAME_CONTROL_CLIENT_TO_SERVER_CLUSTER_CMD.toBitmap8());
    builder.setCommandID(ZONE_ENROLL_RESPONSE_ID);
    // Zone Enroll Response:
    // Field 1: 00 - enroll success
    // Field 2: 01 - zone id
    // therefore, final payload is: 0x0001 
    builder.setPayload("0x0001");
    ZCLUnicastMessage message = builder.build();
    
    device.sendProtocolMessage(message.toJson())
          .thenAccept(jsonResponse -> System.out.println(jsonResponse));
}

,
            "manufacturerCode":"0x0000",
            "transactionNum":"0x7C",
            "commandId":"0x01",
            "payload":"0x01436300"
        }
}