Wireless Modems and listening

Is there any way I can make a computer wait for a response from another computer? I know how to send a bunch of information from one computer to another, but what I want is a computer listening for a certain phrase to do something. Can I do this?

to have a computer receive a message you should do:

id,message=rednet.receive()

That is for rednet though, right? I'm talking about wireless modems, if it make any difference. Sorry if it does make a really big difference.

The rednet API uses wireless and wired modems.

Ok… Thanks, I guess… but will the line for receiving messages in the modem API wait for a message?

Yes, it will wait untill it receives a message, however you could specify a timeout as first argument
for example:

id,message=rednet.receive(1)

This would wait for a message for 1 second, if there is none both id and message will be nil and it will move on.

You also want to make sure your modem is open, otherwise it would be useless to wait for a message :P/>

rednet.open( "<SIDE>" )

and then to listen( as said above )

local id, message = rednet.receive()

Now you can check what the variable 'message' was equal to

if message == "Hello" then
    print( "Hello!" )
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