Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!execu!sequoia!balkan!wrangler!ssbn!bill From: bill@ssbn.WLK.COM (Bill Kennedy) Newsgroups: comp.dcom.modems Subject: Re: Telebit registers Summary: OK, I had a bad idea Message-ID: <2082@ssbn.WLK.COM> Date: 13 Jun 91 14:47:24 GMT References: <2081@ssbn.WLK.COM> <1991Jun12.221820.24046@netcom.COM> Reply-To: bill@ssbn.WLK.COM (Bill Kennedy) Distribution: na Organization: W.L. Kennedy Jr. and Associates, Pipe Creek, TX Lines: 96 bill@ssbn.WLK.COM (Bill Kennedy) writes: [ I asked for some kind of comprehensive description of what the various registers are and what they do .... ] gandrews@netcom.COM (Greg Andrews) replies: > >Well, we're talking about two very different situations here. The S59 >register in the T1600 is indeed documented - the manual is simply missing >some important information about the various options. The S120 and J6S36 >registers are only found in PEP modems - not in the T1600. Correct, my statement was confusing because I was confused. I knew or suspected that S120 and S36 were PEP only since that was the problem I was (with Telebit help) chasing. I didn't mean to suggest that Mercedes mechanics should answer Lexus questions but that's the way I wrote it, sorry. >S120 and J6S36 are undocumented on purpose. Several years back, when they >were first created, those registers were fully documented as a means to >make PEP handle adverse phone line conditions gracefully. And they do, indeed, change the behavior of the PEP interview. I regret tp report that there is no combination of settings that has solved the problem over the cellular link, but there sure were differences in how the modem on my end behaved. I also got another call back from Telebit where the fellow patiently explained what each one does and the good and bad ways that they might and did interact. He was also very helpful in handling my "And when none of those work?" question but his nightmare scenario suggestion didn't work either. At this point it appears to be a cultural (firmware differences?) problem between the modems. Having stomped through the swamp, I would have been farther out in left field had it not been for Telebit's guidance; tip 'o the hat to them. >Suddenly, lots of people people started calling tech support to complain >that their PEP connections were running slowly. It turned out these folks >were playing with the registers when they didn't need to. They thought >it was required to adjust the registers for long distance calls. In the >process they were affecting their interactive responsiveness. Several email messages to this effect and some further reflection make me reluctantly agree. Eons ago I served in submarines and there is a category of individual who can not be tolerated on a submarine crew. We called them "valve twisters". A valve twister is a nusiance at best, in some settings they can kill you. It's too bad that there are people who are irresistably drawn to a big "keep out" sign or who persist in "Gee, that looks interesting, I think I'll see what it does...". They waste an awful lot of time and sometimes manage to blame their vendor for their bone headed misadventures. >To solve the problem Telebit removed the registers from the documentation. >If someone is having trouble with their connection, they can call tech >support for help, and they'll get advice on the register adjustments. >Everyone else won't mess with the registers, and therefore won't shoot >themselves in the foot. I'll confess that the crosshairs on my bazooka are in the shape of toes, but I'm not a valve twister. My curiosity is legitimate but I must reluctantly agree that publishing such data, even suitably disclaimed with skull and crossbones, can create more problems than it solves. My preference is to RTFM six or seven times and then not try anything daring unless I'm wrapped around the axle of a problem. In this case the better way is to m'aidez for a coach. That doesn't work with all vendors but it does with Telebit. I succeeded in getting my two TB+'s so twisted up that they couldn't talk to each other over a local call! >I'm sure there will be folks who post the S120/J6S36 settings, either >in this newsgroup or in private e-mail. Some of those settings are >rather old, and may not work as well with newer versions of firmware. Probably so and more likely some valve twister will get something so badly wedged that they'll claim that Telebit modems are all defective. I'm reminded of an article years ago that warned of some register settings for a Hercules monochrome card that would send the monitor flyback into sure and sudden meltdown. That was fair enough, but there were several articles posted, following up, confirming that those settings really did permanently toast their monitor(s). If only for that reason I'll resist the temptation to tell everyone how you can cross up these undocumented registers (it was not among the compatibility warnings from tech support, but close) such that two otherwise healthy Trailblazers stop talking to each other on a local call. I'm still curious but based on Greg's (and the others, Thanks!) remarks, I withdraw the question. The pain of stupidity is so much sharper than the pain of ignorance. On this one I'll opt for ignorance. Sorry for the bulk, but with modems and related gear becoming intelligent to the point of brilliance, sometimes it's better that the safety nets have trained operators. > >-- > .------------------------------------------------------------------------. > | Greg Andrews | UUCP: {apple,amdahl,claris}!netcom!gandrews | > | | Internet: gandrews@netcom.COM | > `------------------------------------------------------------------------' -- Bill Kennedy internet bill@ssbn.WLK.COM or ssbn!bill@attmail.COM uucp {att,cs.utexas.edu,pyramid!daver}!ssbn.wlk.com!bill