40 and 56 MB configurations are only possible when the ***NO LONGER MANUFACTURED*** NUpowr processor upgrade card is installed. The 117 MHz and 167 MHz cards both had 8 MB onboard, and the 183 MHz version had 24 MB onboard.
Apple sometimes advertises this as a 50 MHz machine, since the clock speed is doubled inside the processor chip. However, all I/O to the processor is done at 25 MHz.
One of the configurations sold by Apple contains 12 MB of memory. This configuration requires the removal of the factory-installed 8 MB memory module in order to upgrade to a larger capacity memory module.
Serial Port with the phone icon supports synchronous modems, with handshaking on both the output and input.
