dempson@actrix.gen.nz (David Empson) writes:
>The Workstation Card must look like a bootable device, i.e. it must have
>at least the $Cn01/3/5 ID bytes.  Beyond that, it doesn't need to
>provide a block driver, but does need to provide character I/O support
>(for printing).  I suspect it doesn't support the Pascal 1.1 protocol,
>since this would have a conflicting ID byte at $Cn05.

I just read some info on the Workstation Card at the tilarchive.
It confirms my earlier guesses. Not quite sure how it knows when to
switch from Disk ][ mode to Super Serial mode. Note the last paragraph below.
The hardware specs are 2MHz 65c02, 16KB RAM, 64KB ROM & SCC.

  Software
  --------
  The Apple IIe Workstation Card contains AppleTalk code in ROM, code to 
  allow printing over the network, printing at the workstation, and 
  starting up over the network. The Apple IIe Workstation Card can start 
  up either from a local disk, or remotely over the network from a startup 
  server running on a file server.

  Local Startup
  -------------
  When the workstation starts up from a local device, the card makes 
  itself look like a Super Serial Card, with special ID bytes to indicate 
  that it is actually an Apple II Workstation Card.

  Network Startup
  ---------------
  The card emulates a Disk II drive on power up to enable network startup, 
  and, if in the highest number slot (normal practice) downloads the 
  operating system from a network startup server, if available.

  In addition, either of these other two methods can be used to start up 
  over a network:

  - Use the PR# command specifying the card's slot and hold down the Open
  Apple key while pressing Return. (Issuing the PR# command and pressing
  Return without pressing the Open Apple key causes printing to take 
  place.)

  - Using a BOOT call also causes the startup process to take place.

  Printing Over the Network
  -------------------------
  The printing task begins when you issue a PR# command from the 
  workstation. The application program sends print data out through the 
  SSC entry points as defined by the PR# command. The card captures the 
  stream of characters to be printed, because it appears to be a normal 
  Super Serial Card in a slot and sends it to the selected printer or 
  spooler.

  Only ProDOS applications are supported on the network using the card. An 
  important feature of the card is that it does not require the use of 
  main memory, because most applications use all or almost all of Apple 
  IIe memory (including "reserved" areas).
--
David Wilson  School of IT & CS, Uni of Wollongong, Australia