Subject: Re: IrDA?
To: None <firstname.lastname@example.org>
From: Calvin Vette <email@example.com>
Date: 01/28/1999 11:54:39
A few datapoints:
1) On the surface, the layers look similar to the AppleTalk protocol (has the
same key elements)
2) I believe Lego Mindstorms are IrDA compliant
3) On my Compaq LTE 5380, the IrDA port is accessible as a serial port.
4) I believe the HP 48 series calculators also use IrDA hardware compatible
ports. I'm not as sure about this, though.
Pete Bentley wrote:
> firstname.lastname@example.org wrote:
> > > The prices of Nokia 6150 GSM phones are dropping and.. and.. :-)
> > But does it speak IrDA? I have a 6110 and it only uses the
> > lowest level of the IrDA stack, the rest is proprietary Nokia
> > stuff. Otherwise they couldn't charge outrageous amounts
> > for their comm software. :-(
> I don't believe it does. According to one source[*] the 6110, 6150, 8110
> and nk702 all require Nokia software. The Nokia 8810, Ericsson SH888 &
> DI27 all talk IrDA though (IrCOM).
> > > I wonder if IrDA protocol could be implemented as a user-level protocol
> > > or if kernel support would be required..
> > You can do it in a user process.
> Indeed, although I think some of the timings are a bit tight, so a
> user-level implementation might run slow if it drops packets and
> requires retransmits.
> On the other hand, given the complexity of the protocols I think the
> free Unix community would benefit from a portable, user-space IrDA stack
> or some sort (perhaps just a daemon that created a mapping from certain
> TCP ports to certain IrDA service end-points). As far as I know the
> Linux people are going for a kernel implementation, so that's not going
> to be much use to anyone else.
> I did make a start on such a thing about 2 years ago, but was hampered
> by the hardware I was using (SS10 + serial IrDA dongle, talking to a
> Psion 3c which doesn't exactly have the best IrDA stack in the world
> anyway) and eventually ran out of time...
> I guess the reason no-one else has bothered either is the complexity.
> To get a simple serial stream from one computer to another you have to
> implement at least 4 layers:-
> * A hardware 'driver' layer to program whatever serial to IR device
> you're using
> * IrLAP - Link access, neighbour discovery, datagram layer
> * IrMUX - Service discovery and connection, "stream" layer
> * IrComm - Serial line emulation over IrMUX
> Then if you want to do interesting stuff like data-exchange (eg
> automatically passing people your business vCard) there's a whole object
> exchange protocol on top of IrMUX you'll be wanting.
> IrDA is truly a protocol suite that has suffered badly from being
> designed by a committee... but I still think it would be a cool thing to
> implement under Unix.
> With the rise of IrDA compliant ports on PDAs, phones and printers,
> there are potentially a lot of cool applications (plonk your phone or
> PDA on the desk next to you workstation and it just hot-syncs[**]
> [*] A phone/SMS manager for the Psion Series 5 that can communicate via
> IrDA to certain phones. Me, I use it with a serial cable to an olde
> Ericsson GS18 though.
> [**] Oh yeah, that reminds me... I seem to recall they do very little to
> address security/authentication issues in IrDA. Still... it can be done
> at the application layer.