There are many old data-centric applications that, for historical reasons, use direct modem connections to exchange data between Client and Server. Nowadays, local and global TCP/IP networks have made the direct modem connection obsolete.

Here's why: When you use a direct modem connection, you need to have a physical modem installed on each PC that needs to exchange data. You also must use a physical phone line. This makes the line busy and may even be costly, if long distance calls are required. Modem transfers are also not secure. A hacker doesn't even need to have an access to your phone line. Your data can be easily intercepted with a remote phone line scanner. In a TCP/IP network, on the contrary, you can use the power of a VPN (Virtual Private Networking), SSH or any other secure tunnel to ensure privacy and security.

There are a lot of reasons to move from a direct modem connection to TCP/IP networking. But, how can you do this without investing thousands into new...