Where do I find a Macintosh modem cable?

The Apple IIe Card emulates many of the expansion cards and peripherals one might install in a bare Apple IIe through the use of the host Macintosh's hardware instead, including a 1.44 MB 3.5" SuperDrive, mouse, 1 MB RAM, 80-column text and graphical monochrome or color display, clock, numeric keypad, serial printer and modem ports, SCSI hard drive, and AppleShare file server. An included "Y-cable" enables one to attach up to two external 140 KB 5.25" floppy disk drives, an 800 KB "intelligent" 3.5" Unidisk, and a joystick or paddle control for use with the hard-coded Apple IIe emulator. An 800 KB 3.5" platinum or 1.44 MB SuperDrive will not work when attached via the Y-cable.