Micro-Altair tape interface

As I finally complete my Micro-Altair kit from Briel Computers, my thoughts turn to the question of how I can get an audio tape interface working on this machine. I understand that the MITS tape controller is essentially a serial port with a simple modem bolted on the rear. The Micro-Altair has only one serial port, coming off the ramdisk board, which will be used for the console (no, I don't want to use the built-in terminal). How can a second serial port be added to this machine? Then for recognizing Kansas City tape tones, I suppose I could clone the circuitry of the tape drive modem. Then I realized I could make an Arduino do this with a handful of other common parts. I could make it recognize Tarbell and other tape formats. Has anyone else done this sort of thing? -- David Griffith dave at 661.org A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?