From owner-freebsd-questions Thu Jun 17 22: 5:48 1999 Delivered-To: freebsd-questions@freebsd.org Received: from WEBBSD1.turnaround.com.au (webbsd1.turnaround.com.au [203.39.138.49]) by hub.freebsd.org (Postfix) with ESMTP id B7D9714D67 for ; Thu, 17 Jun 1999 22:05:40 -0700 (PDT) (envelope-from ajohns@TurnAround.com.au) Received: from tasajohns (dhcp64.turnaround.com.au [192.168.1.64]) by WEBBSD1.turnaround.com.au (8.8.7/8.8.7) with SMTP id PAA12257; Fri, 18 Jun 1999 15:21:29 +1000 (EST) (envelope-from ajohns@TurnAround.com.au) From: "Andrew Johns" To: , "FreeBSD Questions" Subject: RE: Null-Modem? Date: Fri, 18 Jun 1999 15:04:53 +1000 Message-ID: <000f01beb948$1a080670$4001a8c0@tasajohns.turnaround.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <199906180447.AAA07698@cc942873-a.ewndsr1.nj.home.com> X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 Importance: Normal Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG A null-modem cable is a cable with the correct wires crossed/joined - typically if all you want is software flow control (not the best but it works) just connect pins 2,3 and 7 in a DB25 serial port connector (aka V35 connector) and swap pins 2 and 3 at one end. Pin 2 is transmit, 3 receive, 7 ground; so you've got: One end: Other end: TX 2 --------\/------------- 3 RX RX 3 --------/\------------- 2 TX Gr 7 ----------------------- 7 Ground Config your machine for software flow control (XON/XOFF) and it'll send ^S (XOFF) when it's buffer is full and ^Q (XON) when it's ready to receive again. If you don't have access to cables that you can hack/cut/modify, you'll need to buy one - any decent computer shop will have them. As for the BIOS, look for a "Halt On" option in the BIOS and change it to Halt On "No Errors" - "All Errors" is probably the default and "Keyboard" will probably be another option (checks for the presence of a keyboard). Halt on "No Errors" will allow the machine to boot without a keyboard attached. I don't know off the top of my head whether the Phoenix BIOS has this particular option or not. Good luck... HTH Microsoft: Keeping brain-dead administrators in work for ever (fixing/maintaining/rebooting it). > -----Original Message----- > From: owner-freebsd-questions@FreeBSD.ORG > [mailto:owner-freebsd-questions@FreeBSD.ORG]On Behalf Of > Crist J. Clark > Sent: Friday, 18 June 1999 14:48 > To: FreeBSD Questions > Subject: Null-Modem? > > > I've been considering the possibility of using some ol' Wyse terminals > we have laying around (from the retired VAX, may it rest in peace) to > connect one terminal head to serveral FreeBSD machines (I have a > switch from those ol' days too). > > Now, I would think from a hardware end it should be as easy as > plugging the right adapter into the terminal, run the other end of the > wire into an adapter that nicely fits in the serial port of the > FreeBSD machine. > > However, I go look at some FAQ and Handbook sources, and the term > 'null-modem' comes up. Sometimes the context makes 'null-modem' sounds > like what it says, null, nothing, nada. Other times, it sounds like a > null-modem is either an adapter or special wire of some type. > > So, just what is a null-modem if it is anything at all? > > > Oh, one thing tagged on here. There is no need for a 'regular' > keyboard on this machine (or sc0, but I'll leave the card in there), > but the BIOS likes to refuse to boot if no keyboard is hanging off of > of the usual port. I was not able to find a way to turn that off in > the BIOS setup (PhoenixBIOS). Anyone have a work-around for that? Or > is there some obscurely named option in the BIOS setup to do that? > > (Just last night I was doing a RELEASE to STABLE build on a machine, > and I forgot I had removed the keyboard before telling it to reboot > the new kernel. Had to wait until I got to work the next day and > crawled under my desk to plug a kb in to see if all went well. :/ ) > -- > Crist J. Clark cjclark@home.com > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message