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Asynchronous Serial Faqs

FAQs

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

Jul 30th 2011

 SeaLINK Ethernet serial servers use RFC-2217, the Telnet COM port control protocol, to transmit modem control signals in serial tunneling mode. Since S … View More

Asynchronous Serial Faqs

FAQs

What is the extra data transmitted between Sealevel Ethernet Serial Servers and the SeaLINK driver?

Apr 29th 2011

 The extra data is non-serial Telnet command messages such as COM port settings and modem control signals. SeaLINK devices communicate using the RFC-2217 … View More

Asynchronous Serial Faqs

FAQs

How can I optimize my SeaLINK Ethernet serial server for lower latency?

Apr 2nd 2011

 To optimize a SeaLINK Ethernet serial server for lower latency, disable Nagle’s algorithm on both the SeaLINK device and virtual COM port driver. … View More

Asynchronous Serial Faqs

FAQs

Why is my Ethernet serial connection timing out or not responding fast enough?

Apr 2nd 2011

 By default, SeaLINK Ethernet serial servers use Nagle’s algorithm to reduce network traffic and increase serial data throughput, with the side effect o … View More

Asynchronous Serial Faqs

FAQs

How can I improve the performance of my USB to serial adapter?

Mar 31st 2011

 Sealevel USB serial adapters are supported by the SeaCOM driver, which includes a latency timer with a default setting of 16 msec. Decreasing this value redu … View More

Asynchronous Serial Faqs

FAQs

How to fix “crazy mouse” syndrome with USB serial adapters

Mar 1st 2011

OverviewThis condition is potentially encountered in Microsoft Windows when connecting a serial GPS device to a serial port. It is caused when the NMEA 0183 GPS … View More

Asynchronous Serial Faqs

FAQs

Why does the mouse cursor randomly jump around when I connect a GPS to a Sealevel serial adapter?

Feb 2nd 2011

You are describing the “crazy mouse” syndrome, a common condition when Microsoft Windows receives NMEA 0183 data from a serial GPS device. The conditio … View More

Asynchronous Serial Faqs

FAQs

Why don’t standard asynchronous serial adapters support 9-bit protocols?

Sep 1st 2010

 Applications that require 9-bit protocols are rare so the chips that support them are more expensive than standard 8-bit UARTs. Most 8-bit UARTs can simula … View More

Asynchronous Serial Faqs

FAQs

What Sealevel asynchronous serial adapters support 9-bit protocols?

Sep 1st 2010

 Any Sealevel asynchronous serial adapter that includes a 16C950 UART or 16C954 quad-port UART natively supports 9-bit framing in hardware. USB serial ada … View More

Asynchronous Serial Faqs

FAQs

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

Sep 1st 2010

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 e … View More

Asynchronous Serial Faqs

FAQs

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

May 1st 2010

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 … View More

Asynchronous Serial Faqs

FAQs

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

May 1st 2010

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 … View More

Asynchronous Serial Faqs

FAQs

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

May 1st 2010

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 … View More

Asynchronous Serial Faqs

FAQs

Which Sealevel asynchronous serial adapters support isochronous communication mode?

Feb 26th 2010

 Most of our bus based adapters, including PCI Express, PCI, PCMCIA, PC/104 and ISA, can be used. The adapter must have a 16C950 UART installed and suppor … View More

Asynchronous Serial Faqs

FAQs

How does the performance of Sealevel Ethernet serial servers compare to native serial ports?

Jan 13th 2010

Sealevel Ethernet serial servers are designed to mimic the behavior of native PC serial ports. Legacy software can communicate with the Ethernet serial server&rsqu … View More

Asynchronous Serial Faqs

FAQs

Will RS-530 serial devices work with Sealevel RS-422 or RS-485 serial interfaces?

Dec 9th 2009

 Yes. An RS-530 to RS-422/485 interface cable will be required to match up the signal pin outs of the interfaces. Use the CA176 cable to connect the DB25 connec … View More

Asynchronous Serial Faqs

FAQs

What pins should I connect when performing a loop back test? Do all pins need to be connected?

Dec 9th 2009

 Only the data pins (TX and RX) are necessary for a loop back test. Unless you need to test the modem control signals (RTS, CTS, DCD, DTR, DSR, and RI) there is … View More

Asynchronous Serial Faqs

FAQs

What 3rd party software programs work with my Sealevel product?

Dec 9th 2009

Sealevel products are tested with many popular software programs. The 3rd Party Software Support page has a list of these programs with links to application notes th … View More