What type of connector is typically used at the fax end of a fax modem?

The correct choice is RJ-11, which is a type of connector commonly used for telephone lines, including those utilized by fax modems. Fax modems connect to traditional telephone lines to send and receive fax transmissions, and RJ-11 connectors are specifically designed for these types of telephone connections.

This connector features a smaller size and has fewer pins than other types of connectors, such as RJ-45, which is used for Ethernet networking and would not be suitable for fax communication. USB connectors, while widely used for connecting peripherals to computers, are not typically used at the modem end for faxing. HDMI is primarily used for transmitting video and audio signals and is not relevant to fax transmission. Thus, the use of RJ-11 is essential for connecting fax devices to the telephone network, making it the correct answer.