What the heck is a null modem?

[phendish]

I happened to be in radioshack the other day, and someone was asking about buying a null modem. He said he needed it to get on the net (when asked which ISP, it was broadband) I shouldn't have eavesdropped, but my interest was piqued.
Can anyone explain to me what a null modem is, it's purpose, etc? Thanks.

*edit* RadioShack didn't have them in stock, but they did claim that they carried them. Of course, that was said by a guy who has BS'ed me before.

 

[Paiynn]

Read here:
http://www.vision.net.au/~timotsc/null/nullmodem.htm

 

[phendish]

Thanks so much! That answered all of my questions, actually.

 

[Paiynn]

Yeah its not actually a modem, but a cable I could have added that I spose

 

[ken257]

Way back when, I'm talking 8088 and 80286 days I used a null modem cable to trasfer files from PC to PC and from PC to Laptop. Things were just a tad primative as compared to now

 

[phendish]

Now I have another question. Why would he need one to connect to the internet? He's running a network? That sounds doubtful, but it's the only probable thing I can reason.

*edit* I suppose my curiosity on that question will never be satisfied.

 

[Kingslayer]

Rule #1 when you are new to computers and need help.....DO NOT, I repeat, DO NOT go to Radio Shack

They're bigger idiots there than anywhere else.

 

[phendish]

lol Ambient and I were in there looking at voltage meters.

I'd rather go to compUsa for computer help than radioshack.

 

[Pinky]

Rule #1 when you are new to computers and need help.....DO NOT, I repeat, DO NOT go to Radio Shack

They're bigger idiots there than anywhere else.

I had a good experience with the Crossgates Radio Shack here in Albany. I asked the sales guy for some thermal compound and that I was overclocking (when I was first getting into it). He didn't even blink, and walked directly to it. I got the impression he was one of you . Had a similar experience with the same rep a month later looking for a particular case fan.

hehe... Compusa is the "best" of the 'we kinda have an answer, and if we don't know we'll actually say so' computer stores. Best Buy will spread disinformation knowingly to make sales.

 

[Placid]

Now I have another question. Why would he need one to connect to the internet? He's running a network? That sounds doubtful, but it's the only probable thing I can reason.

*edit* I suppose my curiosity on that question will never be satisfied.

My router has a serial port connection on the back that can be used to access it and requires a null modem cable.
Mine is used mainly to get into the setup if you forget the password.

 

[Paiynn]

Now I have another question. Why would he need one to connect to the internet? He's running a network? That sounds doubtful, but it's the only probable thing I can reason.

*edit* I suppose my curiosity on that question will never be satisfied.

Dunno, you cant use a null modem cable to connect to the internet though, that type of connection doesnt use TCP/IP.

The serial ports on routers are used for accessing the box locally for configuration. New routers have to be configured that way since they have no IP address so you cant very well telnet into them. Comm. servers work the same way.

 

[phendish]

Thanks! I think I'll start eavesdropping at Radioshack more frequently.