Date: Tue, 19 Feb 2002 16:18:43 +0800 From: Raymond <[EMAIL PROTECTED]> Subject: Re: [LIB] Some answers please?
At 11:56 PM 18/02/2002 -0800, you wrote: >Date: Tue, 19 Feb 2002 15:51:43 +0800 >From: Raymond <[EMAIL PROTECTED]> >Subject: Re: [LIB] Some answers please? > >At 06:12 PM 18/02/2002 -0800, you wrote: >>Date: Mon, 18 Feb 2002 20:08:18 -0500 >>From: "Pres Waterman" <[EMAIL PROTECTED]> >>Subject: Re: [LIB] Some answers please? >> >>don't overclock it). What do you need to run off the serial port? It might >>well be faster/easier to use the infrared serial port, its a (relatively) >>trivial matter adapting most serial devices to run off that. Of course, your >>OTHER problems >> >>Please explain how to take the following serial devices and trivially adapt >>them to IrDa so I can easily use them with my Libretto: > > >well there are a number of ways of doing things. They're (relatively) low speed so if >you were willing to take them apart (and if you're lucky!) you can get the raw RX/TX >lines from whatever device you're looking at BEFORE the RS-232 driver IC and pipe >them through to an IrDA tranciever (I got a few Agilent HSDL-1001-011 low-speed IrDA >compliant trancievers for about $4USD or so which I was going to play with, there are >higher speed ones such as the HSDL-1100-018 but they're more complicated to play with >due to more signal shaping components required). If you're unlucky you'll find that >the signals emerge from the microprocessor already at RS-232 levels so you'll need to >use the alternative idea. Both trancievers should give you at least a foot of >transmit distance with a visible angle of a bit over 90� (thats being conservative, >I've had better but things start going loopy). Gah! OK I forgot to mention one thing. Two things actually. OK three. 1: This will ONLY work on devices that need only Tx and Rx lines because thats all that your IrDA port on your PC effectively has (so your serial mice, standard serial modems and some of your unpowered barcode scanners won't work because they need the other signal lines). Of course, you could always fudge these as normally they're stuck in one state or another anyway. If in doubt, break out the signal when the device is normally plugged into the computer and see what the RTS/CTS, DTR/DSR and CD/RI lines are doing. Whatever you do, don't let these lines float, it might work sometimes but other times the device might wait forever for a RTS/CTS handshaking signal that never comes. I've not come across this problem because most of my mucking around isn't with modifying existing hardware but according to a quick google, http://www.airborn.com.au/rs232.html recons that RTS and CTS should be looped back onto themselves (like a null modem). The flow control lines DTR/DSR would be trickier to deal with ... dunno how you'd handle those. As for CD/RI, apart from modems and mice (which leech their power from a number of the control lines) I don't think anything else actually USES them so you might be safe just tying them to whatever their states are normally. Oh ya, and when I say tying high or low, they'd be RS-232 levels which are nominally plus or minus 12 volts or so ... if you're using a MAX232 you'll have a spair TX/RX pair (because the MAX232 caters for both TX/RX as well as RTS/CTS) so just tie the extra voltage pump buffer high or low and you'll have your plus or minus 12 (however, if you need to tie some lines to plus 12 AND some lines to minus 12 then you'll be in a pickle ...). 2: I forgot, another company that makes those trancievers is Infineon (sp?) and that Agilent is actually part of HP if you're wondering where they popped out from. 3: Your software and OS has to be able to treat the IrDA port as just another serial port. Note that Win95 with the IrDA patch has 2 modes of operation, the 'proper' IrDA operation (needed for such things as wireless modems, printers and so on) and 'old' mode where it treats the IrDA port as a stock standard serial port ... IIRC thats the mode you'll have to be in because the 'proper' mode has a pile of other plug and play, autoscan junk (which obviously won't work with a 'hacked' IrDA tranciever at the other end because it won't know how to reply to the autoscan PnP signals). You'll need to install some patched somethingorother to get the thing doing serial port emulation under Win2k as by default, Win2k treats the IrDA port as a 'weirdo' device and not a serial port. If you have a Nokia mobile phone (or even if you don't) you can download Nokia's data suite for 2k and that has a driver that'll let you do similar things with the IrDA port under 2k (ie. make it look and act like another serial port) but I'm not *too* familiar with it so again your milage may vary. Hope this helps! - Raymond --- /~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\ | | "Does fuzzy logic tickle?" | | ___ | "My HDD has no reverse. 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