# COM Port Setting

[back to Content]

Basic Settings:

Auto Enumerating COM Number for Selected Ports:
This option will enumerate the selected COM port number. The [COM Number] setting is the begining COM number.

COM Number:
The number of COM port (COM1~COM4096) for the selected COM port. The number will always apply to the first port of the selected collection.

Enable Redundant COM
This option is for Redundant COM mapping only. Also you can change to single IP mapping by un-checking this option.

Advanced Settings:

Tx Mode: Hi-Performance/Classical
To improve the write performance, you can select the "Hi-Performance". The behavior of "Classical Mode" is more like the system COM1 which the WriteFile() call is only finished when all queued serial data are send out.

FIFO: Enabled/Disabled
For some slow device, you need to disable the FIFO to improve the latency.

Network Timeout: 500 - 20000 ms
You can use this option to prevent blocking situation if target NPort is not available.

Auto Network Re-Connection:
This is useful for NPort come back from power lost. Driver will send "check alive" packet in background. In this situation, if driver can not reach NPort it will try to re-establish the TCP connection with NPort until ok. In this time, driver will return STATUS_NETWORK_UNREACHABLE if you enable "Return error if network is unavailable" while calling any Win32 Comm function.

Return error if network is unavailable:
You can use this option to detect host network problem. If host network is unavailable, you will get error return code STATUS_NETWORK_UNREACHABLE" while calling Win32 Comm function. This usually means your host loses network connection, maybe the cable is disconnected. If NPort is power off or disconnected but your host network is still available (you can reach other network device), the driver will not report any error. You need to enable "Auto Network Re-Connection" for this option.

Fast Flush:
Win32 Function PurgeComm with PURGE_TXCLEAR will clear all queued application, it will call this function for each transaction so you will get low throughput. you can enable this function. Driver will only clear the data queued in the local firmware through the USB to clear the data queued in the firmware buffer.

Always Accept Open Requests:
When enabled, the NPort driver will always accept requests to open a virtual COM port, even if communications with the device can not be established. With this option, the NPort driver will agree to open a virtual COM port on the system even if the port is blocked or the Ethernet connection is disabled. If this is the case, the connected device will not receive and transmit data even though the system has opened a virtual COM port.

Serial Parameters:

These options will be saved on registry and used on few applications such as serial printer driver. In general case you can ignore these settings.

Security

Enable Data Encryption
Enable the SSL encryption for data transmission of the COM port. In Redundant COM mode, the security function is not supported.

Keep Connection:
If your COM port, with data encryption enabled, will be opened/closed very frequently and NPort is used by only one host, it is recommanded to enable this option for quicker operations. A COM port with encryption enabled will take a short time(300~500ms) while opening because of SSL protocol. By enabling this options, the COM port connection (SSL) will always be kept connected. In this case, opening/closing the COM port will be quicker. In Reverse RealCOM mode, the "Keep Connection" is not supported.

IPv6 Settings

Inteface Index
The Interface Index is for Link-Local address mapping only. Ignore the setting if the mapping addres is not a Link-Local(e.g, fe80::0/64) one. If the COM port is mapped with a link local address, the interface index must be assigned for routing issues. This setting is used to tell the windows system which interface the data should be routed to.