Date: Thu, 21 Feb 2002 11:30:46 +0800 From: Raymond <[EMAIL PROTECTED]> Subject: Re: [LIB] Some answers please?
At 07:11 PM 20/02/2002 -0800, you wrote: >Date: Wed, 20 Feb 2002 22:02:38 -0500 >From: David VanHorn <[EMAIL PROTECTED]> >Subject: Re: [LIB] Some answers please? > > >> >>I was more talking the fact that if it did multiplex the DTR/DSR, RTS/CTS and CD/RI >lines onto the TX/RX lines in software (and the IrDA dongle on the other end >reconstructed them) you'd not be able to hit 115200 and you'd experience a >significantly higher processor overhead as the processor now has to do what the >serial driver chip would have done ... > > >It does sort of, but that's not what happens. >The handshake is generated by your IRDA interface, according to the link state, and >the rate at which the other end can take data. Umm ... right in that case tell me, how would the IrDA dongle pass the various handshaking lines onto the normal (DB9 or DB25) serial device connected to it given that both that device and its driver back on the laptop would be expecting standard Tx/Rx, DTR/DSR, RTS/CTS and CD/RI, a total of 4 full duplex lines, WITHOUT the use of a driver shim on the PC end to multiplex the handshaking lines onto the standard IrDA stream (which, at the lowest level is a single full duplex connection)? >On the other end, handshake is from the peripheral to the irda device, and events >here, you may never see. Same is true in the other direction. >The one thing they DONT do, is echo the handshake lines of the peripheral directly >back to you. Ya thats true but remember, we're trying to trick a device into using a single full duplex IrDA link as a standard 4x full duplex hardwired serial link. Or at least that dongle thing will have to if its going to be a universal serial link emulator ... otherwise one could just wire a transceiver straight into the TTL level TX/RX signals ... >> if the things were designed to permit IrDA printing though I doubt this would be >done because as I said, all printers really need is TX/RX (and software flow control). >> >>Oh and yes proper IrDA devices negotiate the link speed based on conditions but >remember, we're trying to trick non-IrDA devices to link into IrDA ... unfortunately >not many standard serial devices will autonegotiate a speed. > >That's only happening on the IRDA link. >On the cable, that's up to dipswitches and such. ya but the problem is if the standard serial device is expecting, say, 115200 as would the driver on the PC end, it doesn't leave the IrDA dongle much room for autonegotiation ... on the other hand if both the serial device and its driver expect 9600 then that dongle has no point in moving up to 115200. Remember, IrDA devices under Win9x can operate in at least 2 modes, proper IrDA (plug and play scanning, LPT and COM port mapping and so on), and legacy mode where all you get are the raw Tx and Rx signals at a set speed. - Raymond P.S. When I say 'Serial device' I'm talking the thing thats normally hardwired. When I say IrDA dongle I mean the Actisys thingy. --- /~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\ | | "Does fuzzy logic tickle?" | | ___ | "My HDD has no reverse. How do I backup?" | | /__/ +-------------------------------------------| | / \ a y b o t | [EMAIL PROTECTED] | | | HTTP://www.raybot.net | | ICQ: 31756092 | Need help? Visit #Windows98 on DALNet! | \~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~/ ************************************************************** http://libretto.basiclink.com - Libretto mailing list http://libretto.basiclink.com/archive - Archives http://www.picante.com/~gtaylor/portable/faq.html - FAQ -------TO UNSUBSCRIBE------- Reply to any of the list messages. The reply mail should be addressed to: [EMAIL PROTECTED] - Then replace any text on the message's subject line: cmd:unsubscribe --------TO UNSUBSCRIBE DIGEST------ Do above but with this on subject line: cmd:unsubscribe digest **************************************************************
