Re: Imagewriter II printer question(s)

[dempson@actrix.gen.nz (David Empson)]

LFessen106 <lfessen106@aol.com> wrote:

> Does anyone have the cable pinouts for a super serial card to an Imagewriter?

Not in electronic form, but I could derive it from memory (again).  Note
that the Super Serial Card has two possible pinouts, depending on the
direction of the TERMINAL/MODEM jumper block.  Ideally it should be
pointing to TERMINAL for connection to any printer.

SSC (DB-25 male)              IWII (Mini-Din 8)

  2  TxD (data in)  <-------   3  TxD-
  3  RxD (data out) ------->   5  RxD-
  4  RTS
  5  CTS
  6  DSR (flow out) ------->   2  HShkIn
  7  GND  ------------------   4  GND, also connect to 8 (RxD+)
  8  DCD
 20  DTR (flow in)  <-------   1  HShkOut

(OK, I had to look up the SSC manual to remember how the flow control is
remapped with the jumper block set to TERMINAL.)

If the SSC jumper block is set to MODEM, then swap pin 2 with pin 3, and
pin 6 with pin 20 (all at the SSC end, or the equivalent at the other
end).

> Can I just get this cable at a macintosh store?

Assuming the Super Serial Card jumper block is pointing to TERMINAL,
then a Mac-to-Modem cable should work.  There could be problems with the
flow control signals, which would result in loss of some data going to
the printer.

A Mac to modem cable with hardware handshaking (now the standard) will
be fundamentally the same as the above, except as follows:

Mini-Din-8 pin 1 (handshake out) goes to DB-25 pin 4 (RTS).
Mini-Din-8 pin 2 (handshake in) comes from DB-25 pin 5 (CTS).
Mini-Din-8 pin 7 (general purpose input) comes from DB-25 pin 8 (DCD).

With the SSC (TERMINAL setting), this cable will not allow flow control
from the computer to go to the printer, which doesn't matter.  It looks
like the SSC firmware checks all the flow control inputs for permission
to transmit, so the alternate routing of HShkOut should be OK.  The
GPI/DCD signal is irrelevant (not connected in the printer).

> How about a 2c+ serial to modem cable?

That is probably the same as a Mac-to-modem cable, but you might run
into flow control problems, due to the serious limitations of the IIc
and IIc+ serial ports.

IIc-aware communications software can avoid the worst problem (cutting
off transmit characters part way through), but software cannot work
around the loss of incoming characters while the modem indicates it is
busy.

> Is that the same cable in reverse?

For the data lines, yes.  See above re flow control.

> Also, I would like to hook up an Imagewriter to a Linux box.  Can it run off
> of parallel or does it need to be hooked to a serial port? 

The ImageWriter II only has a serial port, so you would need to use a
parallel-to-serial converter to get it to work with a parallel port.  A
serial port would be much easier.

The pinout for a IWII to PC serial cable is the same as for the SSC with
the jumper block pointing to MODEM, i.e. the opposite configuration from
the diagram at the start of this article.  (The connector on the PC is
different - either a female DB-25, or a female DE-9, which uses
different pin numbering: TxD is 3, RxD is 2, GND is 5, DSR is 6 and DTR
is 4.)

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand