Null modem what is

With a null-modem cable, users can link two computers to enable direct communication through serial port connections. Typically, null-modem cables utilize RS communications ports for transmission and receipt. Use of these cables may require handshake authentication. Null-modem cables are often used for localized gaming, where two computers are in proximity, or for linking a specific computer to a greater hardware system.

The basic idea of using null-modem cables is that those who are paying for hardware setups can eliminate the purchase of connecting devices or more costly solutions just by using one of these crossover cables. By: Justin Stoltzfus Contributor, Reviewer. By: Satish Balakrishnan. Dictionary Dictionary Term of the Day. Natural Language Processing. Techopedia Terms. In this case, a standard serial cable connects one device with the adapter.

An identical cable connects the adapter to the other device and the crossover is wired inside the adapter itself. The serial hardware handshaking signals may also be wired in an adapter or crossover cable. Depending on the hardware and software on both sides of the connection, this may be enough for communication to proceed. Three additional hardware handshaking signals may be implemented in a null modem. When all three of these signals are asserted, each device recognizes that the other is powered up and connected.

Some null modems may not connect the Carrier-Detect signal, however. Prior to the development of the Universal Serial Bus USB , a null modem was often used to share files between two computers. A direct cable connection was made between the two systems, using their serial ports and a null modem. This null software emulator also supports full HandFlow control and strict baud rate emulation. Electronic Team uses cookies to personalize your experience on our website.

By continuing to use this site, you agree to our cookie policy. Click here to learn more. Toggle navigation Electronic Team, Inc. Olga Weis Nov 25, Table of contents: What is a null modem? Null modem cable: RS null modem pinout and wiring. Virtual null modem emulator. What is a null modem? Null modem cable: RS null modem pinout and wiring As we have seen, null-modem connections are made possible through the use of a null mode cable.

Below are the most common schemes of null modem cables. Virtual null modem emulator As we stated previously, a null-modem cable connection will not provide high-speed data transfer. RS null modem pinout and wiring. Get a download link for your desktop Submit your email address to get a link for quick download on your desktop and get started!

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