Elecraft

Elecraft K3 and ACOM 2000A

Classic

List

Threaded

34 messages Options

David Woolley (E.L)

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

It is a requirement of RS-232 that any interface pin will tolerate a low
impedance short circuit to anything in the range -25V to +25V, so
shorting two outputs together is within specification, even if the
resulting logic level may be indeterminate.

This is only true of compliant interfaces, and not necessarily true of
merely compatible ones.

--
David Woolley
Owner K2 06123

On 14/09/14 16:29, Dick Dievendorff wrote:
> That's surprising, but that's OK as long as you don't try to connect two
> RS-232 transmitters. RS-232 isn't designed for multiple transmitters trying
> to hold TxD at + or - 12V (or somewhere near there).
>
> So if you depend on that amp polling, you wouldn't want to connect a
> computer also.

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Don Wilhelm-4

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

David,

That is true the specification says that condition will not cause damage
to compliant drivers and receivers, but if two drivers are placed on an
RS-232 signal line, they will *not* work together and will result in
corrupt data (assuming they are on the TXD or RXD signal lines).

You are correct that damage may occur to non-compliant (but compatible)
drivers and receivers. The PC serial cards, USB to serial adapters, and
most ham gear do not implement compliant RS-232 interfaces.

73,
Don W3FPR

On 9/15/2014 6:14 AM, David Woolley wrote:
> It is a requirement of RS-232 that any interface pin will tolerate a
> low impedance short circuit to anything in the range -25V to +25V, so
> shorting two outputs together is within specification, even if the
> resulting logic level may be indeterminate.
>
> This is only true of compliant interfaces, and not necessarily true of
> merely compatible ones.
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Lynn W. Taylor, WB6UUT

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

There is the formal standard, and there is the defacto standard.

The formal standard says +3v for 1, -3v for 0, and that less than 3v is
undefined.

The common driver chips (1488 and 1489) worked just fine with TTL levels
-- 5v being above +3, and 0v being close enough to -3v.

I've never seen anything that required -3v for logic zero.

-- Lynn

On 9/15/2014 6:59 AM, Don Wilhelm wrote:

> David,
>
> That is true the specification says that condition will not cause
> damage to compliant drivers and receivers, but if two drivers are
> placed on an RS-232 signal line, they will *not* work together and
> will result in corrupt data (assuming they are on the TXD or RXD
> signal lines).
>
> You are correct that damage may occur to non-compliant (but
> compatible) drivers and receivers. The PC serial cards, USB to serial
> adapters, and most ham gear do not implement compliant RS-232 interfaces.
>
> 73,
> Don W3FPR

Dick Dievendorff-4

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

My point is that multiple transmitters on an RS-232 link aren't likely to
work well because the protocol is point to point, and there is no "collision
recovery" protocol. This isn't an Ethernet cable. It's RS-232. Point to
point, not multipoint.

Even if spec-compliant end point electronics aren't damaged by such a
connection, a receiver is likely to be confused by the competing efforts of
multiple transmitters. One of the transmitters will be attempting to hold
the TxD line at mark, the other at space. Which one wins depends on the
implementation.

Dick, K6KR

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Lynn
W. Taylor, WB6UUT
Sent: Monday, September 15, 2014 8:15 AM
To: [hidden email]
Subject: Re: [Elecraft] [acom-list] Re: Elecraft K3 and ACOM 2000A

There is the formal standard, and there is the defacto standard.

The formal standard says +3v for 1, -3v for 0, and that less than 3v is
undefined.

The common driver chips (1488 and 1489) worked just fine with TTL levels
-- 5v being above +3, and 0v being close enough to -3v.

I've never seen anything that required -3v for logic zero.

-- Lynn

On 9/15/2014 6:59 AM, Don Wilhelm wrote:

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Don Wilhelm-4

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

In reply to this post by Lynn W. Taylor, WB6UUT

The confusion I am trying to clear is that more than one driver on an
RS-232 line will not work properly and will result in erroneous data.

Multiple receivers are no problem.

Besides, you are quoting the standard for the receiver input. In order
to drive the long lines (as originally intended for RS-232), the driver
output must be much greater. Capacitance in the cable and resistance
can distort the waveform and reduce the voltage. Not usually a problem
with short lines encountered in typical PC and ham radio setups, but is
problematic when the line length gets long.
There is a difference between "it works", and "it works right all the time".

73,
Don W3FPR

On 9/15/2014 11:15 AM, Lynn W. Taylor, WB6UUT wrote:

> There is the formal standard, and there is the defacto standard.
>
> The formal standard says +3v for 1, -3v for 0, and that less than 3v
> is undefined.
>
> The common driver chips (1488 and 1489) worked just fine with TTL
> levels -- 5v being above +3, and 0v being close enough to -3v.
>
> I've never seen anything that required -3v for logic zero.
>
> -- Lynn
>
> On 9/15/2014 6:59 AM, Don Wilhelm wrote:
>> David,
>>
>> That is true the specification says that condition will not cause
>> damage to compliant drivers and receivers, but if two drivers are
>> placed on an RS-232 signal line, they will *not* work together and
>> will result in corrupt data (assuming they are on the TXD or RXD
>> signal lines).
>>
>> You are correct that damage may occur to non-compliant (but
>> compatible) drivers and receivers. The PC serial cards, USB to
>> serial adapters, and most ham gear do not implement compliant RS-232
>> interfaces.
>>
>> 73,
>> Don W3FPR
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Lynn W. Taylor, WB6UUT

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

In reply to this post by Dick Dievendorff-4

On 9/15/2014 8:42 AM, Dick Dievendorff wrote:
> My point is that multiple transmitters on an RS-232 link aren't likely to
> work well because the protocol is point to point, and there is no "collision
> recovery" protocol. This isn't an Ethernet cable. It's RS-232. Point to
> point, not multipoint.
Ethernet is multipoint to multipoint because there are protocols on top
of the electrical specification that allow multiple transmitters, and
detect and deal with corrupt data and collisions.

RS-232 doesn't have that level of protocol. I don't have the spec.
handy, but I don't think it goes beyond the electrical specification.

It's possible to put some more elaborate protocol on top of RS-232 and
make it work, but it isn't part of the K3 serial protocol.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

LA7NO

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

The RS-232 standard goes quite far and also covers signalling etc.
Have a look here:

http://en.wikipedia.org/wiki/RS-232

P-T / LA7NO

On 15 September 2014 18:11, Lynn W. Taylor, WB6UUT <
[hidden email]> wrote:

> On 9/15/2014 8:42 AM, Dick Dievendorff wrote:
>
>> My point is that multiple transmitters on an RS-232 link aren't likely to
>> work well because the protocol is point to point, and there is no
>> "collision
>> recovery" protocol. This isn't an Ethernet cable. It's RS-232. Point to
>> point, not multipoint.
>>
> Ethernet is multipoint to multipoint because there are protocols on top of
> the electrical specification that allow multiple transmitters, and detect
> and deal with corrupt data and collisions.
>
> RS-232 doesn't have that level of protocol. I don't have the spec. handy,
> but I don't think it goes beyond the electrical specification.
>
> It's possible to put some more elaborate protocol on top of RS-232 and
> make it work, but it isn't part of the K3 serial protocol.
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

73,

Per-Tore / LA7NO

Bill Turner-2

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

In reply to this post by Don Wilhelm-4

I'm not a computer expert so maybe this is a simplistic question.

In the future, wouldn't it be better to abandon serial ports and go to
USB for data communicating between radio/computer/amplifier and other
equipment?

With USB, isn't it possible to write drivers that can work with
multiple equipment connections and avoid the "collision" problem?

Or is it not that simple? Is there a better solution?

73, Bill W6WRT
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

LA7NO

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

I would not recommend using USB.
It is not very compatible with RF. It can give noise in the receiver, and
it can malfunction if there is RF radiation close to it. Bluetooth is
definitely better for wireless communication.

P-T/LA7NO

On 15 September 2014 20:12, Bill Turner <[hidden email]> wrote:

> I'm not a computer expert so maybe this is a simplistic question.
>
> In the future, wouldn't it be better to abandon serial ports and go to
> USB for data communicating between radio/computer/amplifier and other
> equipment?
>
> With USB, isn't it possible to write drivers that can work with
> multiple equipment connections and avoid the "collision" problem?
>
> Or is it not that simple? Is there a better solution?
>
> 73, Bill W6WRT
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

73,

Per-Tore / LA7NO

Joe Subich, W4TV-4

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

In reply to this post by Bill Turner-2

> In the future, wouldn't it be better to abandon serial ports and go to
> USB for data communicating between radio/computer/amplifier and other
> equipment?

No - you would need multiple ports/hub to connect multiple devices and
each device would need custom drivers for each operating system with
which it is to be used. Since it would not be possible to know what
other devices are being connected, each device would attempt to act as
"master" of all USB connections.

One would be far better served if the amplifier builders would adopt a
standard interface (or emulate the PW-1 as Tokyo High Power and SPE
did) which would permit a single "smart controller" like microHAM
Station Master to provide an arbitrated/buffered CAT channel from
computer to transceiver, translate the native CAT information to the
form (e.g. PW-1) required by the amplifier and select antennas based
on frequency/band.

The real issue is with amplifiers that don't share CAT properly (e.g.,
they do not provide port sensing/buffering) and insist on polling
rather that being a good passive listener. Port (traffic) sensing
works well if the designer is willing to use a fast microprocessor
to read/relay polling from the computer, buffer polls when necessary
to avoid collisions, and only poll for data that may become "stale."
Otherwise the designer should be a true "passive listener" and never
poll when a transceiver is being controlled by a logging program. It
when the amplifier designer insists on polling without providing the
necessary hardware support that problems start.

73,

... Joe, W4TV

On 2014-09-15 2:12 PM, Bill Turner wrote:

Elecraft mailing list

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

In reply to this post by Bill Turner-2

I personally believe RS-232 is better.

It is far more universal

________________________________
From: Bill Turner <[hidden email]>
To: [hidden email]
Sent: Monday, September 15, 2014 2:12 PM
Subject: Re: [Elecraft] [acom-list] Re: Elecraft K3 and ACOM 2000A

I'm not a computer expert so maybe this is a simplistic question.

In the future, wouldn't it be better to abandon serial ports and go to
USB for data communicating between radio/computer/amplifier and other
equipment?

With USB, isn't it possible to write drivers that can work with
multiple equipment connections and avoid the "collision" problem?

Or is it not that simple? Is there a better solution?

73, Bill W6WRT

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Bill Turner-2

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

In reply to this post by Joe Subich, W4TV-4

------------ ORIGINAL MESSAGE ------------(may be snipped)

------------ ORIGINAL MESSAGE ------------(may be snipped)

On Mon, 15 Sep 2014 14:38:19 -0400, w4tv wrote:

> It
>when the amplifier designer insists on polling without providing the
>necessary hardware support that problems start.

REPLY:

Makes sense.

So, would it be better for an amplifier to have two ports:

1. A receive-only port for band changes
2. A send-only port for monitoring such as temperature, power output,
SWR and whatever else is desired.

When you're paying many thousand $$$ for an amp, the cost of an extra
port seems negligible.

Or is there a better way?

73, Bill W6WRT
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Joe Subich, W4TV-4

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

The designer can do whatever he pleases on a telemetry port -
whether it is of value is debatable.

However, if the designer expects to be able to operate with either a
computer controlled radio or in the absence of computer control of
the radio, he needs to implement two ports - one for the "logger"
connection from the computer and one to connect to the radio. The
amplifier/designer needs to implement a smart controller that will
accept, buffer and forward polling and control commands from the
logging software and interleave that data stream with its own polls
if the logging software is not polling for all of the data (e.g.,
split status) that the amplifier needs to determine the correct
transmit frequency. The amplifier controller also needs to forward
any "automatic update information" (e.g. band change data) to the
computer/logger as some logging programs rely on that "auto-
information" in lieu of polling. Finally, the controller needs to
establish a "hard bypass" if the amplifier is turned off or placed
in standby.

All of this is independent of any telemetry which needs to be on a
separate port since most loggers (none that I know of) know nothing
about the amplifier and do not expect amplifier status/telemetry
in the radio control data.

73,

... Joe, W4TV

On 2014-09-15 2:52 PM, Bill Turner wrote:

> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
> On Mon, 15 Sep 2014 14:38:19 -0400, w4tv wrote:
>
>> It
>> when the amplifier designer insists on polling without providing the
>> necessary hardware support that problems start.
>
> REPLY:
>
> Makes sense.
>
> So, would it be better for an amplifier to have two ports:
>
> 1. A receive-only port for band changes
> 2. A send-only port for monitoring such as temperature, power output,
> SWR and whatever else is desired.
>
> When you're paying many thousand $$$ for an amp, the cost of an extra
> port seems negligible.
>
> Or is there a better way?
>
> 73, Bill W6WRT
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Andy McMullin

Re: [acom-list] Re: Elecraft K3 and ACOM 2000A

In reply to this post by Bill Turner-2

USB is also a point to point system. But worse, it's master/slave too. At least with serial both ends are equal; with USB one end must be in charge. That's why devices can't talk to each other, only to a central system.

If you want multiple connections you need FireWire (or IEEE 1394). All devices are the same priority and you can daisy-chain a number of them together. Designed for sharing multiple gizmos on one set of wires. Fast too.

Or implement synchronous RS232 with a poll/response protocol like BISync or U100/UTS400. But that would mean implementing all the pins of the RS232 standard wouldn't it? All 25 pins rather than the cut-down version on PCs?

My gripe? People refer to it as RS232 when the 9-pin system on a PC doesn't implement it. Where's the B channel, the clocks, ring indicator, remote loopback, secondary RTS and CTS, the rate selector? Not there so it's not a true RS232 connector. It's an IBM 9-pin serial instead!!!

<high horse: OFF>

Sorry if there are any typos,
this is sent from my iPad
Andy, G8TQH
Ex-senior instructor comms and terminals; Sperry Univac Europe.

> On 15 Sep 2014, at 19:12, Bill Turner <[hidden email]> wrote:
>
> I'm not a computer expert so maybe this is a simplistic question.
>
> In the future, wouldn't it be better to abandon serial ports and go to
> USB for data communicating between radio/computer/amplifier and other
> equipment?
>
> With USB, isn't it possible to write drivers that can work with
> multiple equipment connections and avoid the "collision" problem?
>
> Or is it not that simple? Is there a better solution?
>
> 73, Bill W6WRT
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]