20 Jul
2010
20 Jul
'10
12:46 p.m.
On 7/19/10, Liam Proven <lproven at gmail.com> wrote:
Every week? I use them every day..
I am very happy to say that I have not used a
serial port for anything
in a good 2-3y now, and not for anything more than a very occasional
sync of my Psion 7book...
I use serial ports every week. I really hate RS232. It is the most troublesome
interface of any kind
on any computer I've ever used. I celebrate its disappearance with joy
and I hope never to have to use such a port again. All the crap with
baud rates, stop bits, parity bits, flow control and all that hateful
1960s-ish nonsense is just a fading memory now and I hope I never have
to refresh it.
It may be hateful 1960s nonsense, but if you know how it works,
presuming you have the ability to control all the parameters of one
end of a connection (software-controlled params, jumpers, straps,
solder bumps, etc), you can still take something made in 1968 and
attach it to something made in 2008. Apple did
serial ports right on the Mac. You plugged things in, they
worked, thankyou and goodnight.
Mac-designed things, sure, but Apple didn't make it easy to talk to
the world full of "standard" serial devices (of which there were
*lots* in the 1980s). I really like
USB.
I really do not like USB. It takes hundreds of cycles and more to
move a simple message, it's a host-based, not bi-directional design,
and it's only available on somewhat newish kit.
The host-based aspect of it is probably my biggest peeve - with a
serial port, it's just TxD, RxD and perhaps some handshaking lines
(more likely in the past, but sometimes supported in recent products).
What that means to me is that I can buy a device that might be
intended as a client (a Palm Pilot, to give a specific and handy
example) and by dropping an app on it, turn what was manufactured to
be a "receptive" device into an "active" device - such as use it as
a
VT100 replacement for configuring Cisco routers (boy my boss's eyes
bugged out when I pulled a Palm out of my pocket, clicked in a serial
cable and fixed something in seconds instead of leaving the room,
retrieving a laptop, setting it up, etc., etc.)
Which is where we came in, the idea of a palmtop machine that could be
used as a terminal.
A USB-equipped Palm is meant to be addressed as a 'peripheral' and
cannot be a 'host' - that limits its usefulness to me.
Makes it useless for me :-)
It has some advantages - power for light-duty
peripherals is great,
simple connectors is great, not having to worry about DCE and DTE
orientation is handy. It's great for mice and keyboards, sure, but
I'm less convinced about higher-bandwidth uses.
Since it's not symmetirc, there are the equivalents of DTEs (host
computers0 and DCEs (peripherals) in USB. The big differnece is that with
RS232 you can make a null-modem adapter to connect 2 DTes or 2 DCEs, it's
just a matter ot wiring up a coule of sockets. You can't do that with USB.
-tony