A device is an example of technology. A null modem cable is a device.

A user guide on networking with a null modem can be found in various places. One place is to check the information that came with the null modem. If one cannot find the answers they seek there, then another place is to check with a networking expert.

A null modem cable is a cable which connects two computers directly. The connection is made using serial interface and actually requires no modem or phone line. These connections can be useful for some legacy applications, however due to the availability of low cost networking equipment null modem connections are now rarely used.

You can find a Null Modem Serial Cable for sale from stores such as Walmart, Tiger Direct and Radio Shack. You can also get these cables from retailers such as Amazon.

try a null modem serial connection