How can two serial devices communicate without using a PC?

  The simplest method is to use a null modem cable (Item# CA213), which reverses the transmit and receive signals between the serial devices. This method only works for short distances. For distances over 50 feet, a better method is to use a pair of Sealevel Ethernet Serial Servers and configure them for “serial tunneling”. […]

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How do I change the COM port assignment for my asynchronous serial adapter?

  Sealevel recommends using the installed COM numbers if at all possible to avoid system conflicts. If you previously installed a USB or PCMCIA serial interface, it will have resources assigned by the operating system. If the device is not currently connected to your computer, these COM assignments will not be apparent and forcing new […]

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How do I perform a loopback test with my serial adapter configured for 2-wire RS-485?

  2-wire RS-485 connects the transmitter and receiver to the same data channel. Many applications are not designed to receive the same data they are transmitting and expect the serial port to be set to ‘No Echo’. Therefore, when the serial port is transmitting data, the receiver is disabled. For this reason an external loopback […]

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How do SeaLINK Ethernet serial servers transmit modem control signals in serial tunneling mode?

  SeaLINK Ethernet serial servers use RFC-2217, the Telnet COM port control protocol, to transmit modem control signals in serial tunneling mode. Since SeaLINK Ethernet serial servers are DTE devices, they follow standard null-modem conventions to tunnel output modem control signals. This is done in two parts as explained below. Setting the output modem control […]

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How does the Sealevel SeaCOM serial driver differ from the Microsoft serial driver?

  The SeaCOM serial driver looks exactly like the Windows driver to your application. SeaCOM uses the same API and calls as the Microsoft driver. However, SeaCOM provides many additional features not provided by the Microsoft serial driver such as: Auto RS-485 RTS control Support for advanced UARTS Interrupt sharing in Windows 95/98 for ISA […]

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How to change asynchronous serial COM Port assignments in Sealevel’s Port Manager or Advanced Ports Utilities

  Sealevel recommends using the installed COM numbers if at all possible to avoid system conflicts. If you previously installed a USB or PCMCIA serial interface, it will still have resources that have been assigned by the operating system. If the device is not currently connected to your computer, these COM assignments will not be […]

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How to change asynchronous serial COM port assignments in Windows Device Manager

  Sealevel recommends using the installed COM numbers if at all possible to avoid system conflicts. If you previously installed a USB or PCMCIA serial interface, it will have resources assigned by the operating system. If the device is not currently connected to your computer, these COM assignments will not be apparent and forcing new […]

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How to configure UART-based serial adapters in Linux

Linux supports the direct use of 16CXXX UART-based devices with drivers included in the kernel sources. Some Sealevel asynchronous serial devices do not currently have their vendor/product IDs included in this driver. It is necessary to either manually identify the UARTs to the driver or modify the driver by adding the vendor/product IDs.   Option […]

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