**** **** <***@***.com> wrote: > What are the expansion options available on the 2c? Nearly all expansion options are external. Applied Engineering did a memory expansion card which operates like the RamWorks (multi-bank auxiliary memory). This plugs into the CPU and MMU sockets, and those chips then plug into the card. Later revisions of the IIc have a dedicated memory expansion slot, for Apple's IIc memory expansion card, which works like Apple's standard slot RAM card for the II+/IIe, i.e. a "slinky". The motherboard contains all the firmware support - the card is almost purely RAM with very little support circuitry required (probably one ASIC to implement the "slinky" address latch). You can also use a Zip Chip or Rocket Chip to accelerate the CPU. The IIc+ has a modem slot, but I don't know if anything was ever made to go in it. It ties into the slot 2 hardware (making use of the existing 6551 on the motherboard), and I expect the external modem port would be disconnected automatically if you plug in an internal modem. > I'm somewhat familiar with what can be done externally, and I realize that > there are no internal slots. Are these slots totally absent from the > design, or are the sockets simply missing from the mainboard? The motherboard hardware emulates the slots, in that you have I/O devices and firmware which appear to be in slots 1-7 as far as the software is concerned. Most of the physical slot signals are missing. For example, there are no IOSEL or IOSTROBE signals - the IIc uses a single ROM that is enabled for all locations in $C100-$FFFF. (The "UniDisk" and later revisions also use bank switching to toggle the entire ROM space between two 15.75 KB banks, to allow for extra code like the SmartPort support and self-test.) The DEVSEL signals probably exist in some form, since there are I/O devices in the address space for slots 1, 2 and 6. -- David Empson dempson@actrix.gen.nz Snail mail: P O Box 27-103, Wellington, New Zealand