College Assignment

[Apprentrice5]

Hi guys,

i am in the middle of a networks college unit, and i have been given a question that is a little bit out of my knowledge and was just wondering if any one could enlighten me on the subject.

The question is:

'List the uses and limitations of a null modem connection'

Now to my understanding, null modem has now been all but forgotten because of advancements in technology, and that they were mostly used for sharing between two computers. But that is about as far as i understand.

Any help on the subject would be greatly apperciated

Toby

 

[Layback Bear]

If you just Google null modem connection you will get zillions of answers. Google is your friend for homework.

 

[Apprentrice5]

Google was my first place to look, along with every other thing i have to do for college that i dont know. However I cant seem to find the uses of it only ways which it works.

 

[strollin]

A null modem cable is/was used to directly connect two computers together in order to transfer files and such but was also used to attach various serial devices to a computer or to each other. It used the serial ports on the machines and was therefore limited by the speed of the ports such a 9600bps (max of about 119200bps). Basically, it was a cable where the xmit and rcv lines were crossed so that the xmit line of one device was directly wired to the rcv line of the other.

As most computers do not have a serial port these days, there isn't much use for a null modem cable anymore. You can use a USB cable to do the same thing with the proper software and transfer files at a much faster rate since USB 2.0 has a theoretical speed of 480Mbps while USB 3.0 has a theoretical speed of 5Gbps.

 

[mjf]

First Google hit
Null modem - Wikipedia, the free encyclopedia
Typically just a Tx/Rx line swop (hence null modem). The problem is that I can vaguely remember them. To make people think they were getting value for money I saw them put in a box with a lot of air inside.