Ibid uses resistive technology to "feel" the location of your pen or eraser. It uses a standard RS-232 serial cable to communicate with the whiteboard. The whiteboard controller generates up to 192 touch points per second, which are transmitted at 9600 baud to the PC. On the PC side a driver runs under Windows/NT and checks the designated serial port 2000 times per second for incoming data. The front surface of Ibid is actually a thin polyester membrane which is suspended over a solid backing sheet. Each sheet is coated with a conductive film. The writing location on Ibid is determined by applying sufficient pressure for the 2 conductive surfaces to come in contact with each other.