Alex you dont need a 56k for the fact YAC has "IM" type of feature basically it lets you send messages accross the network as well to test or to just send a message across network so you wouldnt need a modem even, Really what the script would be doing is "listen" on the network so when YAC broadcast a message it puts it on screen wether its Name & Number or a Message you broadcasted from YAC on your pc
here is an example from the site:
For Developers and Power Users
YAC has the ability to send short text messages to YAC listeners on the network. This makes YAC a viable addition to home automation or other solutions involving multiple computers and devices on your network.
The YAC Software Developer's Kit is a web page that will help you understand how to write a listener or write a program that will cause YAC to send text over the network on your behalf.
The YACTextSend sample program shows you how to write a simple Windows program that sends text through YAC to listeners on the network. Even if you don't care about the source code, you can use YACTextSend in scripts or from other programs. Just pass the text you want to send on the command line. For instance, to send the string "Does anyone in the house want to go to dinner?", you would type or run:
C:\YACTextSend Does anyone in the house want to go to dinner?
Here is the url to how to for a script on a "listner"
http://sunflowerhead...yac/yac-sdk.htm