Advantech EKI-1352 Setting Serial Parameters, RTS Threshold, Fragment Threshold, Preamble Type

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3.3.4.2RTS Threshold

RTS Threshold is the frame size above that an RTS/CTS handshake will be per- formed before attempting to transmit. RTS/CTS ask for permission to transmit to reduce collisions, but add considerable overhead. Disabling RTS/CTS can reduce overhead and latency in WLANs where all stations are close together, but can increase collisions and degrade performance in WLANs where stations are far apart and unable to sense each other to avoid collisions. If you are experiencing excessive collisions, you can try turning RTS/CTS on or (if already on) reduce RTS/CTS Threshold on the affected stations.

3.3.4.3Fragment Threshold

Fragmentation Threshold is the maximum length of the frame, beyond which payload must be broken up into two or more frames. Collisions occur more often for long frames because sending them occupies the channel for a longer period of time, increasing the chance that another station will transmit and cause a collision. Reduc- ing Fragmentation Threshold results in shorter frames that "busy" the channel for shorter periods, reducing packet error rate and resulting retransmissions. However, shorter frames also increase overhead, degrading maximum possible throughput, so adjusting this parameter means striking a good balance between error rate and throughput.

3.3.4.4Preamble Type

A preamble is a signal used in network communications to synchronize the transmis- sion timing between two or more systems. Proper timing ensures that all systems are interpreting the start of the information transfer correctly.

3.4Setting Serial Parameters

This section explains how to configure EKI-1351/1352 serial communication parameters using this utility. There are various operation modes that are suitable for different application.

Click on the "+" before the model name (e.g. EKI-1522), and the utility will expand the tree structure to show the individual device name. And click on the “+” before the device name, and the utility will expand the interfaces on this device server. Select the serial interface.

EKI-1351/1352 User Manual

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Contents EKI-1351/1352 Product Warranty 2 years Copyright AcknowledgementsSafety Instructions Declaration of ConformityTechnical Support and Assistance FCC Class BSafety Precaution Static Electricity Contents Setting COM Redirector Appendix aChapter Introduction Features SpecificationsPackage Check List Getting Started Understanding EKI-1351/1352 Product DescriptionNormal Mode COM Port Redirector Virtual COM PortMulti-Access Mode Shared COM port mode Multi-Access ModeTCP Server Mode TCP Client ModeUDP Server/Client Mode Serial Tunneling ModeControl Mode LED Indicators HardwareDimensions Units mm EKI-1351 and EKI-1352Back View of EKI-1351/1352 Choosing the Location Connecting HardwarePanel/Wall Mounting DIN Rail Mounting 12 DIN-rail StepWireless Connection Power ConnectionSerial Device Server Configuration Utility Serial ConnectionPage Getting Started Page Configuration Configuration Utility Overview Discovering Serial Device Servers Auto SearchingPage Configuration Clear Device List and Search Again Manual AppendingSetting Ethernet Parameters Ethernet BasicWireless Basic Information Wireless BasicsAssociation Information Wireless Basic Settings Site Survey Wireless Authentication Page Wireless Advanced Beacon IntervalSetting Serial Parameters RTS ThresholdFragment Threshold Preamble TypeSetting Serial Port Parameters Setting Virtual COM Operating Mode Parameters Configuration Setting TCP/UDP Server/Client Operating Mode Parameters Configuration Setting Control Operating Mode Parameters AT Commands List Security Configuration Accessible FunctionFulfilling Administrator Functions Port MonitorImport/Export Serial Port Setting Locate Serial DeviceRestore to Factory Default Settings Lock DeviceUpgrading the Firmware Configuration Page Setting COM Redirector Setting COM RedirectorVirtual COM port Auto MappingSetting COM Redirector Manual Mapping Auto Reconnect Property Manual Direct Mapping Virtual COM Port Remove the Virtual COM PortRunning Diagnostic Test Page Appendix a Diagnostic Ad hoc Mode With wireless moduleDiagnostic Infrastructure Mode Without wireless module