QuercusVL Programming Manual4. Communications protocolEach unit can receive and send information through a simple, binary UDP protocol. Themessages will be sent to the unit through port 8051 (can be modified with the setup), and theunit will send messages to port 8050 of the address configured as central system (can bemodified with the setup), where the client application is running.There are two main groups of messages in the communications between the unit and thecentral system:● Events.● Requests (and their responses).An Event is defined as a message sent by the unit to notify the central system of a happening(arrival of an incidence, activation of a digital output, etc.). An event must be responded to bythe central system within a limited period of time (can be modified in the setup) with an ACK,so that the unit knows that the message has been successfully received. Otherwise, themessage will be sent again until the ACK is received or the maximum number of retries isexceeded (can also be modified in the setup). If an event is answered with a NAK, it will alsobe sent again until the maximum number of retries is exceeded.Example of Events:A message of Request type is a message sent by the client application to a unit to obtainQuercus Technologies125Unit Central systemACKEvent 1Event 4NAKEvent 3Event 2Event 2NAKEvent 3Timeout
