August 2001 - XEmacs-Beta - XEmacs Mailing List Archives

Casey Halverson (InfoSpace Inc)

try laser(a)qth.net .. a very good laser mailing list -----Original Message----- From: Todd Boyle [mailto:tboyle＠rosehill.net] Sent: Monday, August 20, 2001 11:57 AM To: dev(a)seattlewireless.net Subject: RE: IrDA At 08:41 AM 8/20/2001, you wrote: >Check out: >http://www.alphalink.com.au/~derekw/upntcvr.htm >http://www.opticalpaths.com/ > > >I also suspect that that's be harder then you think. The trick is to >get > >it fast. The commercial products don't use powerful lasers, they use >damn > >good optics and signal processing. > >--Justin > > Here is a newsgroup search. There aren't any YahooGroups on the topic. I have not found any mailing lists... http://groups.google.com/groups?as_q=laser%20communication&as_drrb=b&as_mind =29&as_minm=3&as_miny=2000&as_maxd=20&as_maxm=8&as_maxy=2001&num=30

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RE: IrDA 22 years, 8 months

Todd Boyle

At 08:41 AM 8/20/2001, you wrote: >Check out: >http://www.alphalink.com.au/~derekw/upntcvr.htm >http://www.opticalpaths.com/ > > >I also suspect that that's be harder then you think. The trick is to >get > >it fast. The commercial products don't use powerful lasers, they use >damn > >good optics and signal processing. > >--Justin > > Here is a newsgroup search. There aren't any YahooGroups on the topic. I have not found any mailing lists... http://groups.google.com/groups?as_q=laser%20communication&as_drrb=b&as_m...

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RE: IrDA 22 years, 8 months

Casey Halverson (InfoSpace Inc)

>> Patching a laser in instead of the regular diode shouldn't be terribly >> difficult either. >I also suspect that that's be harder then you think. The trick is to get >it fast. The commercial products don't use powerful lasers, they use damn >good optics and signal processing. Microwave is just slightly less picky then light, but not by much! ;-) It is very possible to connect a laser (and some support circuitry) in replace of a low powered IR emitter. Sure, it would probably require the use of an optocoupler, a driver circuit for the laser pointer (partly to keep it from burning up), and some random optics. And yes, laser pointers can modulate very fast. Some have little regulators built in -- this can be as elaberate as a CdS cell in a feedback monitoring fashion or as stupid as a resistor. The resistor trick is becoming more and more common as laser pointer production has reached an all new level of cheapness. (Bad for laser pointer life, good for the laser pen h4x0r) Anyway, these little regulators will limit the frequency greatly -- they need to be taken out if possible. The receiver will have to be a bit different, unless you decide on using an IR laser. If its a photodiode, replace it with one of similar specs in the visable light range. This might be even tricker then the emitter portion. Who knows what the sensitivity of IrDA equipment is. There could be a very elaberate high-gain transimpendence amplifier on it, or it could be similar to your VCR's IR input. I have read about a lot of hacks that amateur operators have done with lasers. Its almost comical what can be done with various household items (more specifically, household 'items' of a geek). And you are right, optics is where its at. You need good band-pass filters, a lens system that can pull as much light in as possible while tightening in on a distant point, and a sensitive receiver. It may sound funny at first, but a long tubular $20 telescope at toys'r'us can do the job. I really think that someone with some spare time, basic high school electronics knoweledge, and the right equipment could create a very usable link. Who knows how far it would work, but i dont think it is as impossible as it sounds. Without counting the laptops with IrDA support (and the possibility of destroying the IrDA port ;-), i can see such a project costing less then $100 easy.

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Re: User accounts 22 years, 8 months

Jeff Nye

I would suggest Mac address filtering at the Access point level. --- Justin Wilson <justin(a)mail.labxpress.com> wrote: > I am in Phoenix, AZ and I am thinking about setting > up an antenna that > points to the park next to my company's office so > the employees of my > company will be able to get on the net from the park > if they want to get > on from their laptops. But the only way I will be > allowed to do this by my > bosses is if I only allow employees to get on, not > the general public. I > was wondering if there is a way to set up some sort > of user authentication > to use it. Keep in mind that I am not connecting my > office LAN to the > wireless network, just providing internet access, so > they will not be able > to authenticate off of my Windows Domain Controller. > The client machines > will be running Windows 2000 and Linux, if that > helps. > > Thanks- > Justin > justin(a)labxpress.com > __________________________________________________ Do You Yahoo!? Make international calls for as low as $.04/minute with Yahoo! Messenger http://phonecard.yahoo.com/

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Re: 23-fyi-tags.patch 22 years, 8 months

Akim Demaille

>>>>> "Paul" == Paul Eggert <eggert(a)twinsun.com> writes: >> Now that I have finally understood how to have this ... XEmacs work >> properly with the `include' TAGS directive, I discovered how useful >> this can be! Paul> Perhaps you can explain it to us? :-) More seriously: does an Paul> explanation belong in the Autoconf manual somewhere? Nope, it's just a plain XEmacs bugs. Well, actually, after some fight I found a relevant comment: etags.el: ;; #### Should make it work with the `include' directive! (defun add-to-tag-completion-table () tags work fine with XEmacs as long as you don't use the completion of tag names :( It's like this since years... Paul> I don't often use XEmacs, so I hope it works with GNU Emacs. I know :) >> +ETAGS_SH = --lang=none --regex='/$[a-zA-Z_][a-zA-Z_0-9]*$=/\1/' >> \ Paul> I'm afraid you'll have to spell out the character ranges, e.g.: Paul> ETAGS_SH = --lang=none Paul> --regex='/$[abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_][abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_0123456789]*$=/\1/' Paul> \ Paul> as 'a-z' isn't portable outside the C locale and (as far as I Paul> can see) there's no guarantee that the regex is interpreted in Paul> the C locale. Arrg. I forgot. Thanks <g> :) Paul> Other than that, the change looks good if it works for you. It does. Thanks for the other reports too!

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JDE package is missing the users guide 22 years, 8 months

Oscar Figueiredo

JDE comes a users guide in HTML format. For some reason it is not included in the XEmacs package though some other docs are... Oscar Figueiredo

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buffers-tab feature: two tabs has the same name 22 years, 8 months

Ilpo Nyyss=f6nen

I use xemacs to edit java files and those files tend to have long names. The buffers-tab cuts those long names and as a result, if I have two long names with the difference in the end, I get two tabs with the same name. It seems that the buffers-tab uses the names of the tabs as keys when selecting the buffer and with two tabs with the same name and therefore I am not able to switch between those two tabs. 1) Is there any workaround? 2) Will this be corrected in 21.4 and if yes, how soon? (I am using currently 21.4.4.) 3) Separate from this, is there a way to have keybindings for those tabs? ObThanks: Otherwise the buffers-tab is great and useful, thanks for it. -- Ilpo Nyyssönen # biny # /* :-) */

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RE: IrDA 22 years, 8 months

Gerald Pickford

Check out: http://www.alphalink.com.au/~derekw/upntcvr.htm http://www.opticalpaths.com/ -----Original Message----- From: Andrew Hakman [mailto:hakmana＠hotmail.com] Sent: Sunday, August 19, 2001 10:52 PM To: dev(a)seattlewireless.net Subject: Re: IrDA After just last month working on an optics project at the International Summer Science Institute that dealt heavily with optics, I would have to agree that radio waves are much easier to work with, and more forgiving if something isn't exactly precisely right. I, personally, would stick to radio for that reason (and a lack of time to get something to the precision level required for optics). Andrew > > Everybody keeps talking about custom optical bridges and such, but > > what about powerboosted IrDA links? Some guys at a MacHack a few years > > back did something clever with lenses, diodes and a PowerBook (or was > > it iMac?) to extend an IrDA link over a fair distance (50 yards or > > something). Could we not find some good optics and do the same thing >Yes, IrDA *can* be made to work over longer distances. In fact, several >of the Ir network links that have been hacked together are using >IrDA. The protocol has a fair amount of overhead that really detracts >from the raw speed. > > > over a much greater range? Not only would we be able to boost the > > power as much as we want (no FCC, right?), it would also be difficult > > to eavesdrop in two ways: #1 you have to find the beam, and #2 you > > have to grab a piece of it without burning yourself. >Well..*someone* is going to complain if you hook up a 2MW laser:) > > > Most newish > > (1999 on or so) laptops and desktops have full speed (4Mbps) IrDA > > built in, making amps and optics shouldn't be terribly difficult. >Bother of these things are probably more difficult then building a decent >yagi antenna. I also suspect that the PowerBook's weren't communicating >at 4mbps either. > > > Patching a laser in instead of the regular diode shouldn't be terribly > > difficult either. >I also suspect that that's be harder then you think. The trick is to get >it fast. The commercial products don't use powerful lasers, they use damn >good optics and signal processing. >--Justin > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp

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(no subject) 22 years, 8 months

Prasad, Venkatesh

unsubscribe

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Re: IrDA 22 years, 8 months

Andrew Hakman

After just last month working on an optics project at the International Summer Science Institute that dealt heavily with optics, I would have to agree that radio waves are much easier to work with, and more forgiving if something isn't exactly precisely right. I, personally, would stick to radio for that reason (and a lack of time to get something to the precision level required for optics). Andrew > > Everybody keeps talking about custom optical bridges and such, but > > what about powerboosted IrDA links? Some guys at a MacHack a few years > > back did something clever with lenses, diodes and a PowerBook (or was > > it iMac?) to extend an IrDA link over a fair distance (50 yards or > > something). Could we not find some good optics and do the same thing >Yes, IrDA *can* be made to work over longer distances. In fact, several >of the Ir network links that have been hacked together are using >IrDA. The protocol has a fair amount of overhead that really detracts >from the raw speed. > > > over a much greater range? Not only would we be able to boost the > > power as much as we want (no FCC, right?), it would also be difficult > > to eavesdrop in two ways: #1 you have to find the beam, and #2 you > > have to grab a piece of it without burning yourself. >Well..*someone* is going to complain if you hook up a 2MW laser:) > > > Most newish > > (1999 on or so) laptops and desktops have full speed (4Mbps) IrDA > > built in, making amps and optics shouldn't be terribly difficult. >Bother of these things are probably more difficult then building a decent >yagi antenna. I also suspect that the PowerBook's weren't communicating >at 4mbps either. > > > Patching a laser in instead of the regular diode shouldn't be terribly > > difficult either. >I also suspect that that's be harder then you think. The trick is to get >it fast. The commercial products don't use powerful lasers, they use damn >good optics and signal processing. >--Justin > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp

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XEmacs-Beta August 2001