Very Computer

by **Walter Harm** » Tue, 30 Jun 1998 04:00:00

For an experiment i need a RS485 adapter card (a sort of serial card).
Is there a card with a linux driver available ?

walter

--
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"This is not my planet, I didn't choose to be here, I don't want
to get involved, just get me out of here, and get me to a party
with people I can relate to!"
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by **Lee Alle** » Wed, 01 Jul 1998 04:00:00

> For an experiment i need a RS485 adapter card (a sort of serial card).
> Is there a card with a linux driver available ?

Most of the RS485 adapter cards emulate RS232 adapters, so Linux would
not know the difference.
The only place you might get in trouble is if you are planning to use the
RS485 in "multi-drop" mode: half-duplex communications on a single pair
of wires.

There are external RS232-to-RS485 adapters (eg, Black Box catalog) that
you can attach to your RS232 port.
Some of them will control the RS485 half-duplex-on-single-pair using the
RS232 handshake signals.

If you have any further questions, please email me: I don't regularly
monitor this area.

Lee Allen
(please remove the "nothere" from my reply-to address)

by **Stephane Corb** » Tue, 07 Jul 1998 04:00:00

Lee Allen a crit:

> > For an experiment i need a RS485 adapter card (a sort of serial card).
> > Is there a card with a linux driver available ?

> Most of the RS485 adapter cards emulate RS232 adapters, so Linux would
> not know the difference.
> The only place you might get in trouble is if you are planning to use the
> RS485 in "multi-drop" mode: half-duplex communications on a single pair
> of wires.

I assume that if Walter want a RS485 adapter card is to do sync
communicationlike HDLC so what is the advantage of RS232 emulation ?

Quote:> There are external RS232-to-RS485 adapters (eg, Black Box catalog) that
> you can attach to your RS232 port.

True.

I know that some HAM cards have a Z8530 and the driver use it in synchronous
mode,
it can be useful.

Stephane

by **Lee All** » Tue, 07 Jul 1998 04:00:00

>I assume that if Walter want a RS485 adapter card is to do sync
>communicationlike HDLC so what is the advantage of RS232 emulation ?

I don't know anything about HDLC, my experience with RS485 has been
async. The RS485 cards that I have used act like RS232 adapters -- in
fact I think they use the same UART. So the PC sees them as RS232.

But the original poster seems to have wandered off, so it seems a
waste of time & energy to argue about what it was he wanted to
accomplish.

Lee Allen Leadtec Systems, Inc.

--- replace "nospam" with "com" in my email address ---

by **Walter Harm** » Wed, 08 Jul 1998 04:00:00

>>I assume that if Walter want a RS485 adapter card is to do sync
>>communicationlike HDLC so what is the advantage of RS232 emulation ?
>I don't know anything about HDLC, my experience with RS485 has been
>async. The RS485 cards that I have used act like RS232 adapters -- in
>fact I think they use the same UART. So the PC sees them as RS232.
>But the original poster seems to have wandered off, so it seems a
>waste of time & energy to argue about what it was he wanted to
>accomplish.

i have a string of probes attached to a rs485 bus. We want to move to linux
so the questions is if there are drivers for rs485 cards ? or somebody
who uses successfull such a think ?

walter

--
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"It is... um... somewhat... uncomplimentary, Captain; Herbert was a minor
official, notorious for his rigid and limited patterns of thought."
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Very Computer

Linux and RS485 board ?

Linux and RS485 board ?

Linux and RS485 board ?

Linux and RS485 board ?

Linux and RS485 board ?

Linux and RS485 board ?