Using Express Modem SW With PowerBook Fax/Data Modem This information only applies to PowerBook Fax/Data Modem (2400 bps) users. Using the Express Modem software with the PowerBook Fax/Data Modem requires that the Serial Tool be installed in your Extensions folder. The Serial Tool is installed in one of two ways: 1) If you already have the older Fax Sender software installed on your system, the Serial Tool will remain on your system after installing the new Express Modem software. 2) You can manually drag the Serial Tool into your Extensions folder. The Serial Tool is posted here in the Networking & Communications:Communication Toolbox folder.