# Difference between tag change scripts and gateway message handler scripts? **URL:** \ **Category:** Ignition\ **Created:** [January 12, 2019, 10:47pm UTC](https://forum.inductiveautomation.com/t/difference-between-tag-change-scripts-and-gateway-message-handler-scripts/21845 "2019-01-12T22:47:35Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [January 13, 2019, 2:06am UTC](https://forum.inductiveautomation.com/t/difference-between-tag-change-scripts-and-gateway-message-handler-scripts/21845/2 "2019-01-13T02:06:55Z")
I think you are begging for trouble trying to read from a serial port in either a tag event or a message handler. You might find this discussion helpful: > [@How to listen serial data without interruption](http://forum.inductiveautomation.com/t/how-to-listen-serial-data-without-interruption/15709): > > I am using serial module to get data from a rs232 device, and the device is could only send its data to serial port ,but could not accept any request. the problem is I don’t know when the data will be send,so I need to listen the serial constantly to avoid lose any data. but unfortunately, there are no any event trigger on serial component in ignition . dose anyone meet the same problem and could give some help? (I’m using ignition 7.7.5) I put scripts on a timer , but datas always los… --- _[View the full topic](https://forum.inductiveautomation.com/t/difference-between-tag-change-scripts-and-gateway-message-handler-scripts/21845)._