What is the maximum modemming speed I can get from my Apple II?
IIe and earlier Apple II’s: These require a serial card which usually plugs into Slot 2. In general, the card determines maximum connection speed for these computers. Many early serial cards max out at 9600 baud. Apple’s Super Serial Card (SSC) and compatible serial cards max out at 19,200 baud. (Lightning Systems made a “Turbo ASB board” add-on for the SSC which extends speed to 230,400. A 1MHz Apple II with the SSC and Turbo ASB should be good for 57.6k baud.) IIc and IIc+: These machines have built-in serial ports which are generally compatible with software specified as requiring a Super Serial Card. Original IIc releases use a cheap method of generating the clock frequency for the serial ports. Most implementations based on the 6551 chip use a 1.8432 MHz crystal, which gives exact baud rates; but, these IIc’s take the master system clock (14.31818 MHz in an American IIc) and divide it by eight to produce 1.7898 MHz. The 3% decrease in clock frequency produces a 3% drop in the baud
