Demise of the COM port?

Max wrote:
> Viktor Kesler wrote:
> 
>> First it was notebooks, now even desktop PCs are made with just
>> one or no RS232 ports.
> 
> RS-232 ports were dropped from the PC specification in 2000 (and
> they started disappearing from Macs before that). Essentially,
> they're obsolete.

And just what is "the PC specification", other than an attempt by
Bill and cohorts to obsolete equipment and software so that they
can foist new collections of bugs and security leaks on us, and
make money in the bargain.

-- 
fix (vb.): 1. to paper over, obscure, hide from public view; 2.
to work around, in a way that produces unintended consequences
that are worse than the original problem.  Usage: "Windows ME
fixes many of the shortcomings of Windows 98 SE". - Hutchison

Robert Wessel wrote:
> 
... snip ...
> 
> And maybe there's a product in here someplace: A more intelligent
> USB->serial adapter without the excessive buffering delays of the
> "conventional" products.

A PCI card with at least two, better four, RS232 ports and two
parallel ports.  However that doesn't fix the problem with
laptops.  Easily available at all the appropriate places for 20 to
50 dollars.

-- 
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
   Available for consulting/temporary embedded and systems.
   <http://cbfalconer.home.att.net>  USE worldnet address!

On Sat, 20 Mar 2004 01:48:42 GMT, CBFalconer wrote:

>No, you should use Telix and a dialling list to various RBBSs.

I think you mean Telex? Or maybe not.

And that really does take me back. I designed a Telex store and
forward switch around a Z80 back in the 80s.

Let's see ... 110 baud, one-and-a-half stop bits, 5-bit baudot codes
... shudder! Oh, and British Telecom's DCE-3 "modem" - AAAAGH!

-- 
  Max

On Sat, 20 Mar 2004 01:48:44 GMT, CBFalconer wrote:

>And just what is "the PC specification", other than an attempt by
>Bill and cohorts to obsolete equipment and software so that they
>can foist new collections of bugs and security leaks on us, and
>make money in the bargain.

My own experience is somewhat different.

I've been running WinXp Pro on my current system for over two years
now. In all that time, the only blue screen I've seen was when the
system disk went toes-up. Not one single crash or stall otherwise. I
do spend quite a lot on high-end hardware, however, and I suspect that
helps a LOT.

Also, the security leaks seem always to be in various MS applications
that I either don't use, or have taken the trouble to sandbox - IIS,
Orifice, and OE, for example. I really don't believe that it's
reasonable to judge all Microsoft products as being of the same
quality - it's quite blatantly not true. Microsoft's best is really
very good, but they don't always reach that standard.

-- 
  Max

Max <mtj2@btopenworld.com> writes:

> Not all that many people upgrade an OS on an existing machine.
> Increasingly, the trend is to only adopt a new OS version when
> replacing the whole machine.

Though I've run across plenty of software that only works on one
particular Windows version.  If upgrading software isn't an option (no
budget) than putting the old OS on a new machine becomes the solution.
I've seen multi-boot machines for this reason; boot into NT for the
compiler and BDM debugger, then boot into 2000 to get USB support
for the logic analyzer.

> So far as I can see, much of the PC's overhead in acting as a USB host
> has been pushed off to hardware (at least in Intel chipsets).

I hadn't realized this.  The serial port stuff is almost totally
handled by hardware in the embedded systems I used.

> > Ie, the PC was used a lot in engineering,
> >much more than Macs, precisely because it could be adapted to a wide
> >variety of uses.
> 
> Which features, specifically, did you have in mind?

Lots of "legacy" ports, lots of card slots, a wide variety of
operating systems to choose from, and at a price that fits into most
budgets (even recycled machines that offices are trying to throw away
come in useful in the lab).

-- 
Darin Johnson
    Gravity is a harsh mistress -- The Tick

D. Zimmerman (7UPdzimmerman@stny.rr.com) says...
>       For the laptop I suggest National Instruments PCMCIA cards.  They 
> have a one and two port model.  They are a little costly, but very good.

Quatech has equivalent products that are a bit less costly:
	http://www.quatech.com/catalog/rs232_pcmcia.php

I would recommend the version with the attached cable.  The detachable 
versions (both Quatech and NI) are quite vulnerable to damage just from 
the weight of whatever you connect to them.

-- Scott 

Grant Edwards <grante@visi.com> writes:

> I've never seen a PC with anything except DB-9 or DB-25
> connectors for RS-232 serial ports.

I was talking about embedded devices, which I assumed the
"not simple" and "not cheap" referred to.

Essentially, the embedded systems use whatever interfaces are the
cheapest, and then the developers and testers have to scrounge up a
way to communicate with it.  From what I can see, serial is cheaper
for embedded devices than USB.

-- 
Darin Johnson
    I'm not a well adjusted person, but I play one on the net.

On Sat, 20 Mar 2004 02:31:47 GMT, Darin Johnson wrote:

>> Not all that many people upgrade an OS on an existing machine.
>> Increasingly, the trend is to only adopt a new OS version when
>> replacing the whole machine.
>
>Though I've run across plenty of software that only works on one
>particular Windows version.

I find that surprising. I've written a lot of code for Windows32 over
the last nine years or so, using both MS and Borland tools, and I've
very rarely come across an undocumented compatibilty issue across
versions. I'd say at least 90% of the Win32 API is fully
backward-compatible, which isn't too bad, considering the advances in
the OS. Stuff I wrote to run on Win95 is still working on XP Pro.

>If upgrading software isn't an option (no
>budget) than putting the old OS on a new machine becomes the solution.
>I've seen multi-boot machines for this reason; boot into NT for the
>compiler and BDM debugger, then boot into 2000 to get USB support
>for the logic analyzer.

I can understand that would be a pain, but I genuinely haven't
encountered the problems you have.
(Mind you, I use VMware to run multiple OSs - much handier)

>> So far as I can see, much of the PC's overhead in acting as a USB host
>> has been pushed off to hardware (at least in Intel chipsets).
>
>I hadn't realized this.  The serial port stuff is almost totally
>handled by hardware in the embedded systems I used.

Sure, but wouldn't you prefer to just handle a single "end-of-message"
event than have to deal with an interrupt for each single character?

-- 
  Max

Dilton McGowan II wrote:
> 
> "rickman" <spamgoeshere4@yahoo.com> wrote in message
> news:405A4DA3.3260FD95@yahoo.com...
> > Viktor Kesler wrote:
> > >
> > > First it was notebooks, now even desktop PCs are made with just one or
> no
> > > RS232 ports.
> > > What's happening?
> > > For us embedded engineers who have developed uC products that
> communicate
> > > with PCs through COM ports, this situation is getting scary.
> > > I know USB/RS232 converters exist, but they're an added cost, very often
> > > make rebooting necessary and are often the cause of delays which can
> cause
> > > problems with protocols that worked well on genuine COM ports.
> > >
> > > The asynch interface may not be fast, but it's cheap, easy to isolate
> > > galvanically and most uControllers have it built in.
> > >
> > > Can we do anything about this trend? Wear 'COM port rulz' or 'USB go
> home'
> > > t-shirts or something?
> >
> > Yes, you can get used to the change and start working *with* USB instead
> > of fighting it.  The mighty oak tree breaks in the wind while the lowly
> > reed bends with it.  :)
> >
> > For example, the give away Cypress PSOC invention board uses USB.  One
> 
> Give away...where? It is $399 on http://www.cypressmicro.com/.

I think you are looking at a different board.  The "invention" board has
two chips an LDO and a crystal, hardly $400 worth.  You are looking at a
development board I expect.  

-- 

Rick "rickman" Collins

rick.collins@XYarius.com
Ignore the reply address. To email me use the above address with the XY
removed.

Arius - A Signal Processing Solutions Company
Specializing in DSP and FPGA design      URL http://www.arius.com
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Viktor Kesler <viktor@cardware.co.yu> says...

>Yes, but we need 9600Bd at up to 1km with a few kV isolation.
>We use a 20mA-loop dongle stuck into the PC COM port. Works like a
>charm and the only thing that can burn it is a lightning strike - and
>even then the PC never gets damaged, only the dongle.
>
>So, building USB into our product doesn't make sense because it's not
>near the PC. We've already got an ethernet tcp/ip module, but that's
>not much use if there isn't already a LAN running around the place.

I fail to see why you think you need a LAN.  If you can run a cable
for your 20mA, you can run a cable for 100BaseT.  Do a web search
on "ethernet crossover cable."

 


-- 
Guy Macon, Electronics Engineer & Project Manager for hire. 
Remember Doc Brown from the _Back to the Future_ movies? Do you 
have an "impossible" engineering project that only someone like 
Doc Brown can solve?  My resume is at http://www.guymacon.com/