Apple II serial cards

Most serial cards have speed ranges starting from 110 bit/s up to 19,200 bit/s, however some can be modified to go much faster.

It offered speeds of 110 and 300 bit/s but with a simple hardware modification (described in the manual accompanying the card) one could change this to 300 and 1200 bit/s, or 1200 and 4800 bit/s.

Unlike the Apple SSC, which used a jumper block to select printer mode or modem mode, the Serial Pro board had two connectors to which the card's ribbon cable could be connected, one for use with a printer and one for use with a modem.

The Serial Pro was a multifunction card which included a ProDOS and DOS 3.3 compatible clock/calendar, freeing up an extra slot for those with highly populated machines.

This card was unique in the sense that it did not use "Phantom Slots" to achieve this functionality.