Newsgroups: comp.sys.apple2.comm Path: news.uiowa.edu!chi-news.cic.net!nntp.coast.net!zombie.ncsc.mil!news.mathworks.com!newsfeed.internetmci.com!news.bctel.net!nntp.pinc.com!freenet.victoria.bc.ca!vifa1!toh From: toh@freenet.Victoria.BC.CA (Marc Sira) Subject: Re: High speed mdm cable? Message-ID: <1996Mar5.060545.928@freenet.victoria.bc.ca> Sender: news@freenet.victoria.bc.ca (News Manager) Organization: Victoria Freenet Association References: <4h5uih$3kk@spectre.star.harc.edu> Date: Tue, 5 Mar 1996 06:05:45 GMT Lines: 71 In our last episode, mattb@gi.alaska.edu (MB) said: >In article <4h5uih$3kk@spectre.star.harc.edu>, gaucho@main.main.com (Erik >Swedberg) wrote: > >> I've asked before, but I've since lost the info. >> Sorry, but once again, has anyone got pinouts for the >> IIgs modem cable? I want to use I guess at least >> a 14.4, hopefullt a 28.8. Also, any other pertinent info >> would be appreciated, like whether my old comm program >> (which runs off floppy (no HDD)) can handle it... > > >I cannot locate my file on the HW handshaking cable off hand, will get >that to you if someone else does not soon. > >However, the IIgs serial port will only handle 19.2k max. You're thinking of the serial port firmware, ie. that which you can adjust via the Control Panel. Many terminal programs talk to the serial port directly, which allows up to 57600. The serial port can handle a 57600 connection. The unaccelerated IIgs can't handle that for a sustained period, but that's the point of using hardware flow control. My Zip 9/32 GS runs at 14.4 compressed and the serial port at 57600, and generally doesn't drop RTS no matter what comes down the line (you can test this by letting your modem respect DTR while using hardware flow control and the proper cable; when the modem abruptly hangs up, you know the computer couldn't keep up for a moment). Actually, the serial ports can go faster, when using Appletalk (presumably synchronous connections, externally clocked). Here are a couple of melded posts I saved with the cable specs (I built my cable from these instructions): IIgs pinout (Mini-Din-8): looking at the back of the plug, or the socket in the IIgs: 8 7 6 5 4 3 2 1 IIgs Modem Mini-Din-8 D25M Function 1 HshkOut 4,20 RTS and DTR 2 HshkIn 5 CTS 3 TxD- 2 TxD 4 Ground 7 Signal Ground 5 RxD- 3 RxD 6 TxD+ (not connected at modem) 7 DCD 8 DCD 8 RxD+ (connect to ground, i.e. pin 4 at IIgs or pin 7 at modem) The DTR connection (pin 20) is optional. It allows the modem to be used in non-handshaking mode with the IIgs output signal going to DTR, allowing it to be used to hang up (AT&D2). If using hardware handshaking, you must include &D0 in the initialization string, to ensure that the DTR input will be ignored. This cable requires that "short circuits" be placed in the cable. This consists of creating a "Y" connection between the three pins. On the MINI DIN-8 end, pins 4 and 8 should be connected to each other as well as to pin 7 of the DB25. On the DB 25 end, pins 4 and 20 should be connected to each other as well as to pin 1 of the MINI DIN-8. -- Marc Sira | {ub675,toh}@freenet.victoria.bc.ca | "Your god drinks...p-p-peach nectar!" {aa,xx}382@freenet.carleton.ca '