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, char...@k5ua.com 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:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to w3...@embarqmail.com
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
