What is Inter-Character Delay aka Idletime?

What is Inter-Character Delay aka Idletime?

You can find the inter-character delay option for most of our terminal products in our Web UI under advanced serial options. If you cannot find it there, try logging in via the command line interface (CLI), which can be accessed via a telnet session and using the

#> set port range=x idletime=x

What is inter-character delay (aka idletime)? During normal operation of our devices the serial ports buffer is polled every few milliseconds. The rate of how often they are polled is determined by many factors such as the number of ports on the unit, and whether or not you have the optimization set for throughput or latency. When the ports are polled the data currently stored in the buffer is transmitted out the Ethernet to its remote destination. However, when you use inter-character delay you put a wait on the serial port. The wait is x (the number of milliseconds you enter) milliseconds after the last byte of data is received on the serial port. The device will keep buffering data up, if the number of milliseconds is never reached, until the buffer reaches 1024k when it will send out the data it has buffered.

Why would you want to use this option? Most people will not need to use this option. It can add unwanted delay. However, there are some circumstances where you may need to use this option. For instance, if your application listens on a tcp/ip socket for a connection, grabs the data available and then closes immediately, when in communication with the PortServer you may only get a portion of the data which the application is expecting. This could occur because the serial data was put into two separate TCP/IP packets, and the application did not wait long enough for the second packet to come in. Depending on how the application handles the data, the application may discard the first part of the data believing that the data is missing or corrupt. The application may also re-request the data or generate error messages. The appropriate setting varies depending on how the application is written and the network traffic. Some experimentation may be required to determine the correct value.


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