As you've seen so far, serial ports play a vital role in modem communications. To make sure that your serial ports are ready to do their duty, you might want to set a few properties. Here's how it's done:
Open the Control Panel's System icon, and in the System Properties dialog box that appears, select the Device Manager tab.
Open the Ports (COM and LPT) branch, highlight the COM port you want to work with, and click Properties.
Display the Port Settings tab, shown in Figure 26.1. These drop-down lists set up default communications settings for the port. You don't need to adjust these values for your modem's port, however, because the settings you specify for the modem will override the ones you see here. ...