I typed in modem in Synaptics and found many modem control apts. Not
knowing what you are trying to control I wouldn't know what to search
for. AT commands are what control most modems so a simple CGI script in
any lanquage should do what you want by sending the proper AT commands.
If what you want is simple enough a programmer acquired through rent a
coder on the net should get you going without emptying the bank.