The cable type most likely connected to an expansion card that allows a computer to receive faxes over a VoIP line is CAT3. This type of cable is traditionally used for telephony and would be compatible with standard telephone systems, which aligns with the need to receive faxes. CAT6, although more advanced, is typically used for higher-speed networking and not specifically suited for telephonic connections required for fax over VoIP.
The PS/2 port is a 6-pin mini-DIN connector used for connecting keyboards and mice to a PC compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. BNC, RCA, and DB9 are not mini DIN connectors.