INM 725B Rev 2110913 4 25 SNTP ClientThe SNTP client is available on Port 4 and can be used to synchronise the annunciator withnetwork time.The IP address, of the Server that will provide the time to the device, can be configured via theconfiguration software.When a valid time message is received it can take up to 30 seconds for the device to fullysynchronise all the cards in the unit.To determine the SNTP message is valid the client checks the following fields in the SNTP data:Server IP address – Checks the message is sent from the configured serverMode – Checks the message is from a Server typeStratum – Checks the stratum is not 0 (kiss of death packet)Originate Timestamp – Checks the timestamp of the request matches the originate time in theresponse back from the Server.Transmit timestamp – Checks the transmit timestamp from the server is not 0.If the client receives an invalid response or no response it will double its poll time after everyrequest it sends. A comm’s error will also be shown on the device.So if for example the poll time is set to 60 seconds in the configuration software, the first pollwill happen after 60 seconds if no valid response, the next message will be sent after 120 secs,then 240 etc.This will continue until the maximum poll time of 3600 seconds is reached.Once a valid response is received this will be reset to the configured poll time.
