Path: news.uiowa.edu!chi-news.cic.net!news.math.psu.edu!news.cse.psu.edu!uwm.edu!math.ohio-state.edu!howland.reston.ans.net!spool.mu.edu!munnari.OZ.AU!comp.vuw.ac.nz!actrix.gen.nz!atlantis.actrix.gen.nz!not-for-mail From: dempson@atlantis.actrix.gen.nz (David Empson) Newsgroups: comp.sys.apple2.comm Subject: Re: Serial/Parallel conversion on IIGS Date: 15 May 1996 22:44:02 +1200 Organization: Actrix - Internet Services Lines: 61 Message-ID: <4ncchi$r61@atlantis.atlantis.actrix.gen.nz> References: NNTP-Posting-Host: atlantis.actrix.gen.nz In article , Richard Der wrote: > Help! I'm trying to connect an Apple IIGS to a parallel printer using > a serial to parallel converter. I have a standard Mac/IIGS (MD8-DB25) > serial printer cable. > > The converter is switch selectable to DTE or DCE configuration. If I > were to use the printer cable to connect the IIGS printer port to the > converter, which setting should I use? The terms "DTE" and "DCE" really only apply to DB-25 and DB-9 serial connectors. All devices that use the Mini-Din-8 connectors have the same pinout, except for extender cables and some switch boxes, which may have a mirrored pinout. (Strictly speaking, all Mini-Din-8 devices with the standard pinout are DTEs, because the transmit and receive data lines are described in terms of the device itself, not the connected device.) As we are talking about a serial-to-parallel converter box, the question boils down to this: exactly what is the converter referring to with its DTE/DCE selection? It could be referring to its own serial port, or the cable plugged into it. I suspect it means its own configuration. This would imply that you need to set it to DTE, to match a serial printer. (If you were using a IIgs-to-modem cable, you would have to set the converter to DCE.) > Could someone also post the pin outs on a standard serial printer cable? Some of the flow control lines may vary, but here are the guts. The IIgs serial port is numbered as follows, looking at the back of the computer: 8 7 6 5 4 3 2 1 The wiring for a serial printer cable would be as follows: IIgs Printer (DB-25) 1 Hshk Out ----- 6 DSR (or possibly 5 CTS, or 8 DCD) 2 HShk In ----- 20 DTR (or possibly 4 RTS) 3 TxD- ----- 3 RxD 4 Gnd ----- 7 Signal Ground 5 RxD- ----- 2 TxD 6 TxD+ No connection 7 GPI No connection 8 RxD+ Loop to signal ground (pin 4 at IIgs or pin 7 at printer) (Cable shield should be connected to shielding at the IIgs end, and to pin 1 at the printer end.) By comparison, a modem cable will swap pins 1 and 2, and pins 3 and 5 (using the numbering of the IIgs end). -- David Empson dempson@actrix.gen.nz Snail mail: P.O. Box 27-103, Wellington, New Zealand