A device you can attach to a personal computer that enables you to transmit and receive electronic documents as faxes. A fax modem is like a regular modem except that it is designed to transmit documents to a fax machine or to another fax modem. Some, but not all, fax modems do double duty as regular modems. As with regular modems, fax modems can be either internal or external. Internal fax modems are often called fax boards.
Documents sent through a fax modem must already be in an electronic form (that is, in a disk file), and the documents you receive are likewise stored in files on your disk. To create fax documents from images on paper, you need an optical scanner.
Fax modems come with communications software similar to communications software for regular modems. This software can give the fax modem many capabilities that are not available with stand-alone fax machines. For example, you can broadcast a fax document to several sites at once. In addition, fax modems offer the following advantages over fax machines:
The principal disadvantage of fax modems is that you cannot fax paper documents unless you buy a separate optical scanner, which eliminates any cost and convenience advantages of fax modems. Another problem with fax modems is that each document you receive requires a large amount of disk storage (about 100K per page). Not only does this eat up disk storage, but it takes a long time to print such files.