[Ham-Computers] RE: infrared port

[Hsu, Aaron (NBC Universal)]

Don,

As others have pointed out, the infrared port on a laptop can be used for
many different things.  The original intent was for "wireless connections"
to peripherial devices such as printers, modems, other computers, etc.
There are several infrared "protocols" of which IrDA is the most common.

Alas, infrared doesn't get much use because it's on the slow side (by
today's standards).  The simplest infrared ports are just an IR LED and an
IR sensor connected to what's basically the TX and RX lines on a serial
port.  Most PDA's that I know of work in this mannor and are limited to
57,600bps or 115,200bps rates.  Older laptops generally support IrDA upto
1Mbps (that's *bits* per second, not Bytes) and newer laptops support upto
4Mbps IrDA.  Unfortunately most IrDA devices that I've seen don't support
the full 4Mbps rate.  Also, really old laptops with the don't even support
IrDA - the infrared port just basically acts like a serial port.

For printing text, 1Mbps is fine, but most print jobs are no longer just
text - they often include a font download for each font and possibly some
raster or bitmap graphics.  IrDA printing is convenient as long as you don't
mind waiting.  Syncing to a PDA is bearable as long as there isn't much data
to be sync'd.  Add a few .JPG's or .MP3's to the sync process and you'll be
waiting quite a while to do a PDA sync.  With the advent of Bluetooth and
802.11b, IrDA will probably slowly disappear.

For now, if you wish to sync with a PDA, you just need to make sure the PDA
and it's sync software support infrared syncing.  PalmOS v3.5 and newer
support IrDA syncs as long as the HotSync software also supports IrDA sync.
On most Palm PDA's, the IrDA sync rate is either 57,600 or 115,200 bps - so
if your PDA supports native USB connections, the USB sync will be much
faster.  If you have one of the newer Palm PDA's with OS5 or newer, then you
can generally "point" the PDA towards a WinXP laptop and WinXP will add a
"drag-n-drop" icon to the desktop for file transfer.  Convenient, but,
again, slow.  I believe that PocketPC devices also support IrDA sync via
newer versions of ActiveSync, but I'm not sure.

BTW, IrDA can also be used with cell phones that have an infrared port.
There's free/shareware available that allows you to manage compatible cell
phones including up/downloading phone lists, ring tones, etc.  Many cell
phones can also act like a cellular modem when "connected" via a laptop's
infrared port.  Again, data rates are limted to under 115,200bps (often
limited to 9,600bps due to technical reason).

If you like to tinker, then the infrared port can also be used as a standard
serial port.  Normally, the infrared driver settings allow you to have the
infrared port emulate a serial port.  You can then access the port via a
standard "COM" port.

73 and have fun with your new toy!

  - Aaron Hsu, NN6O (ex-KD6DAE)
    {nn6o}@arrl.net
    {athsu}@nbcuni.com
    No-QRO Int'l #1,000,006
    . -..- - .-. .-   ".... . .- ...- -.--"