The number and the size of fax documents vary. There are two factors that determine these numbers on your Apple MessagePad.
Free Heap Space:
This is the amount of memory available to the system software to run the Newton. It will determine how large in size the page can be. On average, a fax page takes about 40 KB.
NOTE: If you have trouble receiving a fax, try disabling some of the packages on your Newton MessagePad.
Available Storage Space:
This is the amount of memory you have available on the internal store or a PC card, if you have one. This determines the number of pages you can receive.