I have a Multitech 'MT1432BA' 14.4 fax modem that we are going to be using for Credit Card verification, and I am having problems with it. I have configured the serial port corectly since it will contact modem and get a ready response. Also when I try to dial the lights will activate like they are working, but it just doesn't dial out. I have 2 of the modems, and they both will not do it so I assume that it is a problem with the way that I have set this up, any one have any suggestions or documents they would like to recommend.

To diagnose modem problems you really need a transcript of the connection. If you post one, make sure you remove any sensitive information first!
If the modem is costing you money, I'd suggest investing in a new model. Older modems often suffered from the lack of standards at the time. Newer models can usually be considered more "generic" in operation.
Try using a terminal emulator such as "minicom" to test the modem and your dial-up connection.