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K3S RS232 "Y" Connector causing port conflict

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charles-2

K3S RS232 "Y" Connector causing port conflict

Thanks for the detailed explanation Don. It seems like that is what is
happening, the OM2500 may be sending info back on the line into the "Y"
connector, confusing Na3P on the computer end on making the OM2500 jump
frequency rapidly back and forth between the correct frequency and the
out-of-band phantom frequency. From the responses, there may be 3
possible solutions:

(1) I read N8LP's comment under a different thread heading than this
one. I am using his LP-Bridge program and LP-Pan hardware. Larry said
that I could use one of the extra serial ports in LP-Bridge to send data
to the OM2500A. I think that will work if I put a Serial to USB
converter coming out of the RS232 port on the OM2500A going back to a
USB port on the computer.

(2) If all else fails, I have used DDUTILl in the past to talk to the
OM2500A using the CI-V format into the CI-V port of the OM2500A. I don't
really want to use two virtual serial port programs (DDUTIL and
LP-Bridge), but I might have to try that.

(3) I will email OM Power to ask if I can put the OM2500A into "passive
listener" mode only. I thought that I might be able to accomplish the
same thing by removing the wire in the DB-9 cable that would carry
signals from the OM2500A back to the "Y connector, thereby making it a
"passive listener" by default. If you look at the K3S DB-9 wire
definitions in the manual, one of the wires is RX and one is TX. I was
thinking that if I removed the Line 3 TXD OUT pin from the cable going
to the OM2500A, any signals coming from the OM2500A would never get back
to the "Y" connector to confuse the computer that is listening on the
same line.

On page 18 of the manual there is a table of the DB-9 pin-out. Although
the names of the pins seem counter-intuitive to me.....
Pin 2 (RXD IN) is used to _SEND_ data from the K3 _TO_ the PC and the
OM2500A.
Pin 3 (TXD OUT) is used to _RECEIVE_ data _FROM_ the PC or the OM2500A.

I'm thinking that removal of Pin 3 from the side of the "Y" splitter
that goes to the OM2500A will allow the OM2500A to _RECEIVE_ signals
from the K3S/PC _BUT NOT SEND_ signals to the K3S/PC. Does that make
sense? Would like to receive comments on these three possibilities.

Thanks for all who responded.

Charles K5UA

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Don Wilhelm-4

Re: K3S RS232 "Y" Connector causing port conflict

Charles,

You should find the amp has a driver connected to pin 2.
To make sense of the signal directions, you have to know whether the
device is configured as DCE or a DTE. Data Communications Equipment or
Data Terminal Equipment. The 'transmit' and 'receive' signals are
relative to the DTE. In other words, the signal on pin 2 (RXD) will
have a receicver in the DTE and a Driver in the DCE. The PC is the DTE
and devices like the K3 and your amplifier are DCE type.

I know that the DTE/DCE designation for the PC does not make sense, but
the serial port of the PC started out to be a port which allowed the PC
to behave as a terminal.

73,
Don W3FPR

On 12/14/2015 2:50 PM, [hidden email] wrote:

Cady, Fred-2

Re: K3S RS232 "Y" Connector causing port conflict

You gotta love the RS232 "standard" :-)

In addition to Don's explanation below, you can't rely on any manufacturer to label the signals according to the standard DTE/DCE nomenclature. Some folks think it is just plain wrong to label a signal TXD (transmit data) when it really is a receiving signal line. Or RXD when it is actually transmitting data. That is what pin 3 and pin 2 on the RS232 connector on your K3 are.

About the only sure way to figure out what is an active source is to look at a schematic or measure the pins with a volmeter/scope or get one of the RS232 blinky boxes.

For some more information, have a look at
http://www.ke7x.com/home/miscellaneous-k3-information/unexpected-agc-behavior/rs232-interfaces-1

For even more fun and games, read up on the history and use of the handshaking signals RTS, DTR, CTS and RTS.

Cheers,
Fred KE7X

________________________________________
From: Elecraft <[hidden email]> on behalf of Don Wilhelm <[hidden email]>
Sent: Monday, December 14, 2015 1:25 PM
To: [hidden email]; [hidden email]
Subject: Re: [Elecraft] K3S RS232 "Y" Connector causing port conflict

Charles,

You should find the amp has a driver connected to pin 2.
To make sense of the signal directions, you have to know whether the
device is configured as DCE or a DTE. Data Communications Equipment or
Data Terminal Equipment. The 'transmit' and 'receive' signals are
relative to the DTE. In other words, the signal on pin 2 (RXD) will
have a receicver in the DTE and a Driver in the DCE. The PC is the DTE
and devices like the K3 and your amplifier are DCE type.

I know that the DTE/DCE designation for the PC does not make sense, but
the serial port of the PC started out to be a port which allowed the PC
to behave as a terminal.

73,
Don W3FPR

On 12/14/2015 2:50 PM, [hidden email] wrote:

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Don Wilhelm-4

Re: K3S RS232 "Y" Connector causing port conflict

In reply to this post by charles-2

Charles,

As Fred Cady said in a recent post, it is "all mixed up" and the safest
way to check is to look at the schematic.
It all depends on whether you are a DTE or a DCE device. Prior to the
IBM PC, all was well defined and an RS-232 interface used a DB-25 connector.
AFAIK the IBM PC was the first to use the DE-9 connector for the serial
port connector, and they initially envisioned the PC being used as a
terminal device connected to a large mainframe - so the mix-up began
there - thus the PC is a DTE device, and when things are run from a PC,
the signals are "backwards".
This state of affairs was adopted

In any case, pin 2 is the DE-9 signal line for data *TO* the PC. So the
proper check is for a driver on pin 2 in your amplifier. If your
amplifier also implements other RS-232 signals that use drivers in the
amp, it is likely that those should be disabled as well - check for
drivers on pins 1, 6, 8 and 9 of the DE-9 connector.

And just another twist on the connector designation - the 9 pin
connector commonly used is properly a DE-9. References to it as DB-9
anre quite common, but are incorrect. If you look at the general
category of D-sub connectors, the first letter is properly "D", but the
2nd letter refers to the shell size - "B" is the long connector
typically seen in computer parallel ports, "E" is the smaller shell
commonly used in PC serial ports.
It is usually not important until you get to the typical 15 pin video
port on computers - that is properly a DE-15HD connector. DB-15
connectors also exist, but it is longer and has 2 rows of pins rather
than the 3 rows of the DE-15HD.

Standards are standards, but many manufacturers do not conform to those
standards. Never make the mistake of thinking "it looks like a computer
serial connector, therefore it should be one" - that thought can lead to
damaged equipment. Check the equipment manufacturer's manual. If it is
not marked RS-232, it is not likely to be RS-232.

73,
Don W3FPR

On 12/14/2015 2:50 PM, [hidden email] wrote:

>
>
> Thanks for the detailed explanation Don. It seems like that is what is
> happening, the OM2500 may be sending info back on the line into the "Y"
> connector, confusing Na3P on the computer end on making the OM2500 jump
> frequency rapidly back and forth between the correct frequency and the
> out-of-band phantom frequency. From the responses, there may be 3
> possible solutions:
>
> (1) I read N8LP's comment under a different thread heading than this
> one. I am using his LP-Bridge program and LP-Pan hardware. Larry said
> that I could use one of the extra serial ports in LP-Bridge to send data
> to the OM2500A. I think that will work if I put a Serial to USB
> converter coming out of the RS232 port on the OM2500A going back to a
> USB port on the computer.
>
> (2) If all else fails, I have used DDUTILl in the past to talk to the
> OM2500A using the CI-V format into the CI-V port of the OM2500A. I don't
> really want to use two virtual serial port programs (DDUTIL and
> LP-Bridge), but I might have to try that.
>
> (3) I will email OM Power to ask if I can put the OM2500A into "passive
> listener" mode only. I thought that I might be able to accomplish the
> same thing by removing the wire in the DB-9 cable that would carry
> signals from the OM2500A back to the "Y connector, thereby making it a
> "passive listener" by default. If you look at the K3S DB-9 wire
> definitions in the manual, one of the wires is RX and one is TX. I was
> thinking that if I removed the Line 3 TXD OUT pin from the cable going
> to the OM2500A, any signals coming from the OM2500A would never get back
> to the "Y" connector to confuse the computer that is listening on the
> same line.
>
> On page 18 of the manual there is a table of the DB-9 pin-out. Although
> the names of the pins seem counter-intuitive to me.....
> Pin 2 (RXD IN) is used to _SEND_ data from the K3 _TO_ the PC and the
> OM2500A.
> Pin 3 (TXD OUT) is used to _RECEIVE_ data _FROM_ the PC or the OM2500A.
>
> I'm thinking that removal of Pin 3 from the side of the "Y" splitter
> that goes to the OM2500A will allow the OM2500A to _RECEIVE_ signals
> from the K3S/PC _BUT NOT SEND_ signals to the K3S/PC. Does that make
> sense? Would like to receive comments on these three possibilities.
>
> Thanks for all who responded.
>
> Charles K5UA
>
>
> ______________________________________________________________
> 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]
>

David Woolley (E.L)

Re: K3S RS232 "Y" Connector causing port conflict

Actually, the large mainframe would have been a DTE as well. It is the
modem that is the DCE. The specification is really one for connecting
things to modems.

Initially PCs used 25 pin connectors and they were fairly rare in using
them with the correct gender, male (as defined by the pins) for DTE and
female for DCE. Even after the move to 9 pins, they continued to use
this convention. Therefore, if you have a device that has a male
connector, you can be pretty sure it is configured as a DTE. A female
connector, unfortunately, is not a guarantee of the converse, and the
K2, at least, appears to be non-compliant. It looks like the K3 has the
same non-compliance.

--
David Woolley
Owner K2 06123

On 14/12/15 23:08, Don Wilhelm wrote:

> AFAIK the IBM PC was the first to use the DE-9 connector for the serial
> port connector, and they initially envisioned the PC being used as a
> terminal device connected to a large mainframe - so the mix-up began
> there - thus the PC is a DTE device, and when things are run from a PC,
> the signals are "backwards".

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