[KX3] RS232 xcvr control when serial ports are occupied

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[KX3] RS232 xcvr control when serial ports are occupied

Elecraft mailing list
Hy home station is a KX3 + KPXA100, and I can control the radio via the RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to the station, and its controller plugs in to the KXPA serial port to sniff for frequency information, allowing re-tuning on the fly. This leaves no RS232 port left for remote control of the radio.

How do I modify this arrangement to add an extra serial port for KX3 control? My first thought is that, since the antenna controller just sniffs for data, I could add a DB-9 Y-cable to provide the extra port at the controller serial port location. However, packets could still collide ...does the protocol handle this? Is there some sort of multiplexer available?

Thanks,

Steve

NU7B
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[KX3] RS232 xcvr control when serial ports are occupied

ANDY DURBIN
"My first thought is that, since the antenna controller just sniffs for data, I could add a DB-9 Y-cable to provide the extra port at the controller serial port location. However, packets could still collide ...does the protocol handle this? Is there some sort of multiplexer available?"


If only one device is doing the interrogating then there cannot be any conflict and there is nothing to multiplex. Typically the listening device will only need a 2 wire interface (TXD and GND). My KPA500 just listens to my TS-590 responses to Omni-Rig. Multiple receivers can listen to an RS-232 transmitter, just be careful not to try to make a TX talk to a TX and that may happen if you make a poor choice of Y cable.


73,

Andy k3wyc
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Don Wilhelm
In reply to this post by Elecraft mailing list
Steve,

Are you using the KXUSB to connect with the KXPA100/KX3, or are you
using the KXSER with a real computer serial port or a USB to serial adapter?

Since your magloop controller only 'sniffs', it means it should only
listen and never try to transmit on the RS-232 signal lines.  If it only
listens, there will be no collisons (RS-232 is not packet oriented, but
an asynchronous communications system).

If the magloop controller also transmits on the RS-232 bus, you will
need some external device to act as "traffic cop" - note that RS-232 is
a point to point system (unlike Ethernet and others) where there is one
driver device and one receiver at each end.

So yes, you can use a splitter - one with a 3.5mm stereo plug and two
3.5mm stereo jacks if using the KXUSB.
If you are using the KXSER cable instead, yes, you can connect a "Y" DB9
splitter to the DB9 end of the KXSER cable - the computer connects to
one side and the magloop controller connects to the other side of the "Y".

On 7/8/2018 3:31 PM, Stephen Rector via Elecraft wrote:
> Hy home station is a KX3 + KPXA100, and I can control the radio via the RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to the station, and its controller plugs in to the KXPA serial port to sniff for frequency information, allowing re-tuning on the fly. This leaves no RS232 port left for remote control of the radio.
>
> How do I modify this arrangement to add an extra serial port for KX3 control? My first thought is that, since the antenna controller just sniffs for data, I could add a DB-9 Y-cable to provide the extra port at the controller serial port location. However, packets could still collide ...does the protocol handle this? Is there some sort of multiplexer available?
>
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Dick Dievendorff-4
In reply to this post by Elecraft mailing list
Typically "sniffers" don't have the TX side connected.  RS-232 can't have
multiple transmitters on either wire.

This is done with SteppIR controller, for similar reasons.  SteppIR
describes a splitter cable for DE-9 connectors. The same principle (with a
much simpler cable, just tip and ring) applies to the 3.5mm connector to the
KXPA100.

 http://www.steppir.com/wp-content/uploads/2011/10/Y-Cable.pdf

73 de Dick, K6KR


-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Stephen Rector via Elecraft
Sent: Sunday, July 8, 2018 12:31
To: [hidden email]
Subject: [Elecraft] [KX3] RS232 xcvr control when serial ports are occupied

Hy home station is a KX3 + KPXA100, and I can control the radio via the
RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to
the station, and its controller plugs in to the KXPA serial port to sniff
for frequency information, allowing re-tuning on the fly. This leaves no
RS232 port left for remote control of the radio.

How do I modify this arrangement to add an extra serial port for KX3
control? My first thought is that, since the antenna controller just sniffs
for data, I could add a DB-9 Y-cable to provide the extra port at the
controller serial port location. However, packets could still collide
...does the protocol handle this? Is there some sort of multiplexer
available?

Thanks,

Steve

NU7B
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Elecraft mailing list
In reply to this post by Don Wilhelm
Hi Don:

Yes - it occurred to me after sending the post that I might be able to create the split at the KXPA with a stereo Y-cable/connector. I am using a KXUSB to the computer, with a KXSER cable going from the the antenna controller to the KXPA. It is the KXUSB that presently has no place to connect to.

So - I think I can try a 3.5mm stereo y-junction at the KXPA. Hopefully impedances won't be an issue at 38400 baud...

I did look for RS232 multiplexers - they seem to exist for industrial applications. The documentation seemed to be sparse on the web.

Anyway - thanks for the pointer :)

73,

Steve NU7B


> On Jul 8, 2018, at 1:37 PM, Don Wilhelm <[hidden email]> wrote:
>
> Steve,
>
> Are you using the KXUSB to connect with the KXPA100/KX3, or are you using the KXSER with a real computer serial port or a USB to serial adapter?
>
> Since your magloop controller only 'sniffs', it means it should only listen and never try to transmit on the RS-232 signal lines.  If it only listens, there will be no collisons (RS-232 is not packet oriented, but an asynchronous communications system).
>
> If the magloop controller also transmits on the RS-232 bus, you will need some external device to act as "traffic cop" - note that RS-232 is a point to point system (unlike Ethernet and others) where there is one driver device and one receiver at each end.
>
> So yes, you can use a splitter - one with a 3.5mm stereo plug and two 3.5mm stereo jacks if using the KXUSB.
> If you are using the KXSER cable instead, yes, you can connect a "Y" DB9 splitter to the DB9 end of the KXSER cable - the computer connects to one side and the magloop controller connects to the other side of the "Y".
>
> On 7/8/2018 3:31 PM, Stephen Rector via Elecraft wrote:
>> Hy home station is a KX3 + KPXA100, and I can control the radio via the RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to the station, and its controller plugs in to the KXPA serial port to sniff for frequency information, allowing re-tuning on the fly. This leaves no RS232 port left for remote control of the radio.
>> How do I modify this arrangement to add an extra serial port for KX3 control? My first thought is that, since the antenna controller just sniffs for data, I could add a DB-9 Y-cable to provide the extra port at the controller serial port location. However, packets could still collide ...does the protocol handle this? Is there some sort of multiplexer available?

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Re: [KX3] RS232 xcvr control when serial ports are occupied

Elecraft mailing list
In reply to this post by Dick Dievendorff-4
Hi Dick:

Thanks - the diagram makes things very clear. I initially didn't think of accomplishing the split at the KXPA 3.5mm connector, but it makes sense.

Thanks,  73,

Steve NU7B


> On Jul 8, 2018, at 1:38 PM, [hidden email] wrote:
>
> Typically "sniffers" don't have the TX side connected.  RS-232 can't have
> multiple transmitters on either wire.
>
> This is done with SteppIR controller, for similar reasons.  SteppIR
> describes a splitter cable for DE-9 connectors. The same principle (with a
> much simpler cable, just tip and ring) applies to the 3.5mm connector to the
> KXPA100.
>
> http://www.steppir.com/wp-content/uploads/2011/10/Y-Cable.pdf
>
> 73 de Dick, K6KR
>
>
> -----Original Message-----
> From: [hidden email] <[hidden email]> On
> Behalf Of Stephen Rector via Elecraft
> Sent: Sunday, July 8, 2018 12:31
> To: [hidden email]
> Subject: [Elecraft] [KX3] RS232 xcvr control when serial ports are occupied
>
> Hy home station is a KX3 + KPXA100, and I can control the radio via the
> RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to
> the station, and its controller plugs in to the KXPA serial port to sniff
> for frequency information, allowing re-tuning on the fly. This leaves no
> RS232 port left for remote control of the radio.
>
> How do I modify this arrangement to add an extra serial port for KX3
> control? My first thought is that, since the antenna controller just sniffs
> for data, I could add a DB-9 Y-cable to provide the extra port at the
> controller serial port location. However, packets could still collide
> ...does the protocol handle this? Is there some sort of multiplexer
> available?
>
> Thanks,
>
> Steve
>
> NU7B
> ______________________________________________________________
> 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]
>

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Re: [KX3] RS232 xcvr control when serial ports are occupied

Don Wilhelm
In reply to this post by Elecraft mailing list
Steve,

Yes, since you are using both the KXUSB and the KXSER cables, a "Y" at
the KXPA100 would serve you well.
If your magloop controller also attempts to transmit, you can remove the
connection to pin 2 on the DE9 end of the KXSER cable (just remove the
backshell and disconnect the wire).

RS-232 multiplexors are complicated devices and require the use of the
full RS-232 bus (mainly DTR and CTS signals) to handle the handshaking
signals.  The 3 conductor KX3/KXPA100 wiring will not provide the proper
handshaking signals.
The handshaking signals are not provided from the data stream (as they
are in Ethernet and other communications protocols), but from the
explicit signals separate from TXD and RTS.

Note that the KX3 (and most other Elecraft products) rely only on TXD
and RTS, which are reserved for data transmission only in the RS-232
scheme of things.

73,
Don W3FPR

On 7/8/2018 4:56 PM, Stephen Rector wrote:

> Hi Don:
>
> Yes - it occurred to me after sending the post that I might be able to create the split at the KXPA with a stereo Y-cable/connector. I am using a KXUSB to the computer, with a KXSER cable going from the the antenna controller to the KXPA. It is the KXUSB that presently has no place to connect to.
>
> So - I think I can try a 3.5mm stereo y-junction at the KXPA. Hopefully impedances won't be an issue at 38400 baud...
>
> I did look for RS232 multiplexers - they seem to exist for industrial applications. The documentation seemed to be sparse on the web.
>
> Anyway - thanks for the pointer :)
>
> 73,
>
> Steve NU7B
>
>
>> On Jul 8, 2018, at 1:37 PM, Don Wilhelm <[hidden email]> wrote:
>>
>> Steve,
>>
>> Are you using the KXUSB to connect with the KXPA100/KX3, or are you using the KXSER with a real computer serial port or a USB to serial adapter?
>>
>> Since your magloop controller only 'sniffs', it means it should only listen and never try to transmit on the RS-232 signal lines.  If it only listens, there will be no collisons (RS-232 is not packet oriented, but an asynchronous communications system).
>>
>> If the magloop controller also transmits on the RS-232 bus, you will need some external device to act as "traffic cop" - note that RS-232 is a point to point system (unlike Ethernet and others) where there is one driver device and one receiver at each end.
>>
>> So yes, you can use a splitter - one with a 3.5mm stereo plug and two 3.5mm stereo jacks if using the KXUSB.
>> If you are using the KXSER cable instead, yes, you can connect a "Y" DB9 splitter to the DB9 end of the KXSER cable - the computer connects to one side and the magloop controller connects to the other side of the "Y".
>>
>> On 7/8/2018 3:31 PM, Stephen Rector via Elecraft wrote:
>>> Hy home station is a KX3 + KPXA100, and I can control the radio via the RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to the station, and its controller plugs in to the KXPA serial port to sniff for frequency information, allowing re-tuning on the fly. This leaves no RS232 port left for remote control of the radio.
>>> How do I modify this arrangement to add an extra serial port for KX3 control? My first thought is that, since the antenna controller just sniffs for data, I could add a DB-9 Y-cable to provide the extra port at the controller serial port location. However, packets could still collide ...does the protocol handle this? Is there some sort of multiplexer available?
>
>
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Elecraft mailing list
In reply to this post by Elecraft mailing list
If you are looking at creating a Y splitter (actually the best way for this setup), then be sure to only connect ground and the signal going to the magloop controller.
As someone has mentioned, you do not want to have two devices driving a data signal simultaneously. At some point one will go to +12V, the other to -12V. They will argue and one will win, the other will cease to function.

We were very careful when designing the devices that need to “sniff” the RS-232 cable. The KRC2 has an internal multiplexer that allows it to share driving the signal to the radio in parallel to the one from the computer.
Even still, we advice folks to set one or the other for sending commands to the radio. The KPA500 has an internal relay to enable or disable the data being sent out the PC port. this is controlled by the menu system, allowing
the KPA to perform serial polling (PC port TxD will be enabled) or pure sniffing (TxD disabled).

Note that enabling both devices (computer and antenna controller) to poll the radio can be problematic, even with a multiplexing device. There are some PC applications that can be greatly surprised if they receive a response they didn’t specifically ask for. The surprise generally ends in a crash. Most programs have been rewritten to accept whatever comes there way. I won’t embarrass the problematic program’s authors, but they are aware.

There is one other thing to consider. If you always use the radio and magloop with the computer running, then you are fine. But at some point if you don’t want to use the radio then you will need a source to poll the data. In that case just set the radio to output changes as they occur. That should do the job quite nicely, keeping the magloop controller happy with more data than probably needs to get the job done.

73,
Jack, W6FB


> On Jul 8, 2018, at 2:00 PM, Stephen Rector via Elecraft <[hidden email]> wrote:
>
> Hi Dick:
>
> Thanks - the diagram makes things very clear. I initially didn't think of accomplishing the split at the KXPA 3.5mm connector, but it makes sense.
>
> Thanks,  73,
>
> Steve NU7B
>
>
>> On Jul 8, 2018, at 1:38 PM, [hidden email] wrote:
>>
>> Typically "sniffers" don't have the TX side connected.  RS-232 can't have
>> multiple transmitters on either wire.
>>
>> This is done with SteppIR controller, for similar reasons.  SteppIR
>> describes a splitter cable for DE-9 connectors. The same principle (with a
>> much simpler cable, just tip and ring) applies to the 3.5mm connector to the
>> KXPA100.
>>
>> http://www.steppir.com/wp-content/uploads/2011/10/Y-Cable.pdf
>>
>> 73 de Dick, K6KR
>>
>>
>> -----Original Message-----
>> From: [hidden email] <[hidden email]> On
>> Behalf Of Stephen Rector via Elecraft
>> Sent: Sunday, July 8, 2018 12:31
>> To: [hidden email]
>> Subject: [Elecraft] [KX3] RS232 xcvr control when serial ports are occupied
>>
>> Hy home station is a KX3 + KPXA100, and I can control the radio via the
>> RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to
>> the station, and its controller plugs in to the KXPA serial port to sniff
>> for frequency information, allowing re-tuning on the fly. This leaves no
>> RS232 port left for remote control of the radio.
>>
>> How do I modify this arrangement to add an extra serial port for KX3
>> control? My first thought is that, since the antenna controller just sniffs
>> for data, I could add a DB-9 Y-cable to provide the extra port at the
>> controller serial port location. However, packets could still collide
>> ...does the protocol handle this? Is there some sort of multiplexer
>> available?
>>
>> Thanks,
>>
>> Steve
>>
>> NU7B
>> ______________________________________________________________
>> 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]
>>
>
> ______________________________________________________________
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> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Elecraft mailing list
In reply to this post by Don Wilhelm
Don:

I tried a 3.5mm Y-connector at the KXPA and this did not work. But based on your feedback and also that of N6TV, I see that I have multiple TX drivers on the TXD line. Even if there is no TX from the antenna controller, the low-impedance of its TXD driver will load the line. Bob also thinks the controller may be polling for info, much like the program FLRIG does. One correction to your info Don, I think TXD is pin 3 on the DB-9, and not pin 2.

The KXSER cable DB9 shell appears to be molded - it's not obvious how to disassemble it. So I will need to go into the controller to disconnect TXD there. I'll report back on whether or not that works, next weekend.

73,

Steve, NU7B


> On Jul 8, 2018, at 2:22 PM, Don Wilhelm <[hidden email]> wrote:
>
> Steve,
>
> Yes, since you are using both the KXUSB and the KXSER cables, a "Y" at the KXPA100 would serve you well.
> If your magloop controller also attempts to transmit, you can remove the connection to pin 2 on the DE9 end of the KXSER cable (just remove the backshell and disconnect the wire).
>
> RS-232 multiplexors are complicated devices and require the use of the full RS-232 bus (mainly DTR and CTS signals) to handle the handshaking signals.  The 3 conductor KX3/KXPA100 wiring will not provide the proper handshaking signals.
> The handshaking signals are not provided from the data stream (as they are in Ethernet and other communications protocols), but from the explicit signals separate from TXD and RTS.
>
> Note that the KX3 (and most other Elecraft products) rely only on TXD and RTS, which are reserved for data transmission only in the RS-232 scheme of things.
>
> 73,
> Don W3FPR
>
> On 7/8/2018 4:56 PM, Stephen Rector wrote:
>> Hi Don:
>> Yes - it occurred to me after sending the post that I might be able to create the split at the KXPA with a stereo Y-cable/connector. I am using a KXUSB to the computer, with a KXSER cable going from the the antenna controller to the KXPA. It is the KXUSB that presently has no place to connect to.
>> So - I think I can try a 3.5mm stereo y-junction at the KXPA. Hopefully impedances won't be an issue at 38400 baud...
>> I did look for RS232 multiplexers - they seem to exist for industrial applications. The documentation seemed to be sparse on the web.
>> Anyway - thanks for the pointer :)
>> 73,
>> Steve NU7B
>>> On Jul 8, 2018, at 1:37 PM, Don Wilhelm <[hidden email]> wrote:
>>>
>>> Steve,
>>>
>>> Are you using the KXUSB to connect with the KXPA100/KX3, or are you using the KXSER with a real computer serial port or a USB to serial adapter?
>>>
>>> Since your magloop controller only 'sniffs', it means it should only listen and never try to transmit on the RS-232 signal lines.  If it only listens, there will be no collisons (RS-232 is not packet oriented, but an asynchronous communications system).
>>>
>>> If the magloop controller also transmits on the RS-232 bus, you will need some external device to act as "traffic cop" - note that RS-232 is a point to point system (unlike Ethernet and others) where there is one driver device and one receiver at each end.
>>>
>>> So yes, you can use a splitter - one with a 3.5mm stereo plug and two 3.5mm stereo jacks if using the KXUSB.
>>> If you are using the KXSER cable instead, yes, you can connect a "Y" DB9 splitter to the DB9 end of the KXSER cable - the computer connects to one side and the magloop controller connects to the other side of the "Y".
>>>
>>> On 7/8/2018 3:31 PM, Stephen Rector via Elecraft wrote:
>>>> Hy home station is a KX3 + KPXA100, and I can control the radio via the RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to the station, and its controller plugs in to the KXPA serial port to sniff for frequency information, allowing re-tuning on the fly. This leaves no RS232 port left for remote control of the radio.
>>>> How do I modify this arrangement to add an extra serial port for KX3 control? My first thought is that, since the antenna controller just sniffs for data, I could add a DB-9 Y-cable to provide the extra port at the controller serial port location. However, packets could still collide ...does the protocol handle this? Is there some sort of multiplexer available?

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Re: [KX3] RS232 xcvr control when serial ports are occupied

Don Wilhelm
Sorry about the pin typo.  Look at the cable link for the steppIR that
Dick K6KR sent and that will be obvious.  I was looking at that diagram
when I typed my response, but did not proof it.
TXD is really pin 3.

73,
Don W3FPR

On 7/8/2018 7:24 PM, Stephen Rector wrote:

> Don:
>
> I tried a 3.5mm Y-connector at the KXPA and this did not work. But based on your feedback and also that of N6TV, I see that I have multiple TX drivers on the TXD line. Even if there is no TX from the antenna controller, the low-impedance of its TXD driver will load the line. Bob also thinks the controller may be polling for info, much like the program FLRIG does. One correction to your info Don, I think TXD is pin 3 on the DB-9, and not pin 2.
>
> The KXSER cable DB9 shell appears to be molded - it's not obvious how to disassemble it. So I will need to go into the controller to disconnect TXD there. I'll report back on whether or not that works, next weekend.
>
> 73,
>
> Steve, NU7B
>
>
>> On Jul 8, 2018, at 2:22 PM, Don Wilhelm <[hidden email]> wrote:
>>
>> Steve,
>>
>> Yes, since you are using both the KXUSB and the KXSER cables, a "Y" at the KXPA100 would serve you well.
>> If your magloop controller also attempts to transmit, you can remove the connection to pin 2 on the DE9 end of the KXSER cable (just remove the backshell and disconnect the wire).
>>
>> RS-232 multiplexors are complicated devices and require the use of the full RS-232 bus (mainly DTR and CTS signals) to handle the handshaking signals.  The 3 conductor KX3/KXPA100 wiring will not provide the proper handshaking signals.
>> The handshaking signals are not provided from the data stream (as they are in Ethernet and other communications protocols), but from the explicit signals separate from TXD and RTS.
>>
>> Note that the KX3 (and most other Elecraft products) rely only on TXD and RTS, which are reserved for data transmission only in the RS-232 scheme of things.
>>
>> 73,
>> Don W3FPR
>>
>> On 7/8/2018 4:56 PM, Stephen Rector wrote:
>>> Hi Don:
>>> Yes - it occurred to me after sending the post that I might be able to create the split at the KXPA with a stereo Y-cable/connector. I am using a KXUSB to the computer, with a KXSER cable going from the the antenna controller to the KXPA. It is the KXUSB that presently has no place to connect to.
>>> So - I think I can try a 3.5mm stereo y-junction at the KXPA. Hopefully impedances won't be an issue at 38400 baud...
>>> I did look for RS232 multiplexers - they seem to exist for industrial applications. The documentation seemed to be sparse on the web.
>>> Anyway - thanks for the pointer :)
>>> 73,
>>> Steve NU7B
>>>> On Jul 8, 2018, at 1:37 PM, Don Wilhelm <[hidden email]> wrote:
>>>>
>>>> Steve,
>>>>
>>>> Are you using the KXUSB to connect with the KXPA100/KX3, or are you using the KXSER with a real computer serial port or a USB to serial adapter?
>>>>
>>>> Since your magloop controller only 'sniffs', it means it should only listen and never try to transmit on the RS-232 signal lines.  If it only listens, there will be no collisons (RS-232 is not packet oriented, but an asynchronous communications system).
>>>>
>>>> If the magloop controller also transmits on the RS-232 bus, you will need some external device to act as "traffic cop" - note that RS-232 is a point to point system (unlike Ethernet and others) where there is one driver device and one receiver at each end.
>>>>
>>>> So yes, you can use a splitter - one with a 3.5mm stereo plug and two 3.5mm stereo jacks if using the KXUSB.
>>>> If you are using the KXSER cable instead, yes, you can connect a "Y" DB9 splitter to the DB9 end of the KXSER cable - the computer connects to one side and the magloop controller connects to the other side of the "Y".
>>>>
>>>> On 7/8/2018 3:31 PM, Stephen Rector via Elecraft wrote:
>>>>> Hy home station is a KX3 + KPXA100, and I can control the radio via the RS232 port on the KXPA. However, recently I added a Ciro Mazzoni magloop to the station, and its controller plugs in to the KXPA serial port to sniff for frequency information, allowing re-tuning on the fly. This leaves no RS232 port left for remote control of the radio.
>>>>> How do I modify this arrangement to add an extra serial port for KX3 control? My first thought is that, since the antenna controller just sniffs for data, I could add a DB-9 Y-cable to provide the extra port at the controller serial port location. However, packets could still collide ...does the protocol handle this? Is there some sort of multiplexer available?
>
>
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Re: [KX3] RS232 xcvr control when serial ports are occupied

ANDY DURBIN
In reply to this post by ANDY DURBIN
"TXD is really pin 3."


One end's TXD is the other end's RXD. That's obvious to those who have used RS-233 for a while but if someone needs to ask then it may not be obvious. Find the TXD pin on the source and connect it the RXD pin on the destination. Sometimes it's easier to look with a scope than to try to understand the documentation.


I really like my Rigol DS1054Z which not only allows the waveform to be examined it also decodes the data.


73,

Andy k3wyc


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Re: [KX3] RS232 xcvr control when serial ports are occupied

Don Wilhelm
Andy,

No TXD is TXD all the way through the path.  Yes, the DTE TXD will have
the drivers, and the DCE will have receivers, but it is TXD from end to
end.  RXD is the other way around because the DCE drives that line.
Trsnsmit and receive are named with respect to the DTE.

73,
Don W3FPR

On 7/8/2018 8:39 PM, ANDY DURBIN wrote:
> "TXD is really pin 3."
>
>
> One end's TXD is the other end's RXD. That's obvious to those who have used RS-233 for a while but if someone needs to ask then it may not be obvious. Find the TXD pin on the source and connect it the RXD pin on the destination. Sometimes it's easier to look with a scope than to try to understand the documentation.
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Re: [KX3] RS232 xcvr control when serial ports are occupied

ANDY DURBIN
"No, TXD is TXD all the way through the path.  Yes, the DTE TXD will have the drivers, and the DCE will have receivers, but it is TXD from end to end.  RXD is the other way around because the DCE drives that line.  Transmit and receive are named with respect to the DTE."

That's great when one equipment is designed to be a DTE and the other as a DCE but sometimes that's nor the case.  I think I have connected more equipment with a 2-3 3-2 connection than with 2-2 and 3-3 connection.
Perhaps I should have said  - identify the transmit pin on the source and connect it to the receive pin on the destination.

73,
Andy k3wyc


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Re: [KX3] RS232 xcvr control when serial ports are occupied

Cady, Fred-2
In reply to this post by Don Wilhelm
Hi Andy,

Don is correct.

Here is a little blurb that might help.

http://www.ke7x.com/home/miscellaneous-k3-information/unexpected-agc-behavior/rs232-interfaces-1


________________________________
From: [hidden email] <[hidden email]> on behalf of Don Wilhelm <[hidden email]>
Sent: Sunday, July 8, 2018 7:21 PM
To: ANDY DURBIN; [hidden email]
Subject: Re: [Elecraft] [KX3] RS232 xcvr control when serial ports are occupied

Andy,

No TXD is TXD all the way through the path.  Yes, the DTE TXD will have
the drivers, and the DCE will have receivers, but it is TXD from end to
end.  RXD is the other way around because the DCE drives that line.
Trsnsmit and receive are named with respect to the DTE.

73,
Don W3FPR

On 7/8/2018 8:39 PM, ANDY DURBIN wrote:
> "TXD is really pin 3."
>
>
> One end's TXD is the other end's RXD. That's obvious to those who have used RS-233 for a while but if someone needs to ask then it may not be obvious. Find the TXD pin on the source and connect it the RXD pin on the destination. Sometimes it's easier to look with a scope than to try to understand the documentation.
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Don Wilhelm
The computer is the DTE device, and those devices designed to connect to
the computer via the serial port are normally wired as DCE devices.

The original thought when the IBM PC serial port was designed was that
the PC would be used as a terminal connected to a modem, thus the
decision was that the PC should be a DTE - and for the first several
years the PC was used only as a terminal device.  Yes, I was involved
during those early days, but not as a part of that decision making
process - I was involved with the IBM PC modems.  My manager said I had
"M" engraved on my forehead.

Now we have the situation where the computer is the controller.  It
would be very confusing to change the wiring of the computer, so it
remains as a DTE, and connecting devices (while not modems) are
configured as a DCE,

73,
Don W3FPR

On 7/8/2018 10:15 PM, Cady, Fred wrote:

> Hi Andy,
>
> Don is correct.
>
> Here is a little blurb that might help.
>
> http://www.ke7x.com/home/miscellaneous-k3-information/unexpected-agc-behavior/rs232-interfaces-1
>
>
> ________________________________
> From: [hidden email] <[hidden email]> on behalf of Don Wilhelm <[hidden email]>
> Sent: Sunday, July 8, 2018 7:21 PM
> To: ANDY DURBIN; [hidden email]
> Subject: Re: [Elecraft] [KX3] RS232 xcvr control when serial ports are occupied
>
> Andy,
>
> No TXD is TXD all the way through the path.  Yes, the DTE TXD will have
> the drivers, and the DCE will have receivers, but it is TXD from end to
> end.  RXD is the other way around because the DCE drives that line.
> Trsnsmit and receive are named with respect to the DTE.
>
> 73,
> Don W3FPR
>
> On 7/8/2018 8:39 PM, ANDY DURBIN wrote:
>> "TXD is really pin 3."
>>
>>
>> One end's TXD is the other end's RXD. That's obvious to those who have used RS-233 for a while but if someone needs to ask then it may not be obvious. Find the TXD pin on the source and connect it the RXD pin on the destination. Sometimes it's easier to look with a scope than to try to understand the documentation.
> ______________________________________________________________
> 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
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> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
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>
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Cady, Fred-2
Thanks Don.  It must have been interesting working all that out.  I used to enjoy giving my students a history lesson explaining the control and handshaking signals in the RS232 connector from basic principles, starting with the Bell 103 modem.  That didn't help  explain the terminology and signal naming problem that Andy had. Manufacturers were terrible at keeping to the standard.  And really, in isolation, it doesn't make sense that a signal named TxD would be a input and not an output.  Documentation was scanty and so the scope, or my favorite test tool -- the RS232 Blinky Box -- had to be gotten out to tell what was what.

The now  used for other purposes signals are:
DTR -- from the terminal to the modem to tell the modem the Data Terminal was ready.  Now used for CW or PTT.

DSR -- From the modem to the terminal to indicate the modem was ready (generally power on).

The Bell 103 could send data only in one direction at a time so RTS and CTS were included to control the flow of the data.

RTS -- Request to Send from the terminal to the modem to request the line.

CTS -- Clear to send from the modem to the terminal to say the line was not busy and to go ahead with sending the data.

RTS and CTS were also used to control the data flow from a fast device to a slow device.  I think there were some kenwood radios that used this scheme.

DCD -- Data Carrier Detected was used for the modem to tell the terminal that the carrier from the other data set was being generated (the phone line was working).

RI -- Ring Indicator asserted by the modem when it heard a ringing signal at the other end of the telephone line.

As I remember it.

Cheers,
Fred KE7X




________________________________
From: [hidden email] <[hidden email]> on behalf of Don Wilhelm <[hidden email]>
Sent: Sunday, July 8, 2018 10:04 PM
To: [hidden email]
Subject: Re: [Elecraft] [KX3] RS232 xcvr control when serial ports are occupied

The computer is the DTE device, and those devices designed to connect to
the computer via the serial port are normally wired as DCE devices.

The original thought when the IBM PC serial port was designed was that
the PC would be used as a terminal connected to a modem, thus the
decision was that the PC should be a DTE - and for the first several
years the PC was used only as a terminal device.  Yes, I was involved
during those early days, but not as a part of that decision making
process - I was involved with the IBM PC modems.  My manager said I had
"M" engraved on my forehead.

Now we have the situation where the computer is the controller.  It
would be very confusing to change the wiring of the computer, so it
remains as a DTE, and connecting devices (while not modems) are
configured as a DCE,

73,
Don W3FPR

On 7/8/2018 10:15 PM, Cady, Fred wrote:

> Hi Andy,
>
> Don is correct.
>
> Here is a little blurb that might help.
>
> http://www.ke7x.com/home/miscellaneous-k3-information/unexpected-agc-behavior/rs232-interfaces-1
>
>
> ________________________________
> From: [hidden email] <[hidden email]> on behalf of Don Wilhelm <[hidden email]>
> Sent: Sunday, July 8, 2018 7:21 PM
> To: ANDY DURBIN; [hidden email]
> Subject: Re: [Elecraft] [KX3] RS232 xcvr control when serial ports are occupied
>
> Andy,
>
> No TXD is TXD all the way through the path.  Yes, the DTE TXD will have
> the drivers, and the DCE will have receivers, but it is TXD from end to
> end.  RXD is the other way around because the DCE drives that line.
> Trsnsmit and receive are named with respect to the DTE.
>
> 73,
> Don W3FPR
>
> On 7/8/2018 8:39 PM, ANDY DURBIN wrote:
>> "TXD is really pin 3."
>>
>>
>> One end's TXD is the other end's RXD. That's obvious to those who have used RS-233 for a while but if someone needs to ask then it may not be obvious. Find the TXD pin on the source and connect it the RXD pin on the destination. Sometimes it's easier to look with a scope than to try to understand the documentation.
> ______________________________________________________________
> 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]
>
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Dave Fugleberg
As a ‘field engineer ‘ for a global company in the 80s, I’d occasionally
find one of those RS232 breakout boxes tucked behind some production
system, jumpered to make the connection work, blinking away, because some
technician finally hit upon the magic combination and then left it in place
rather than building a proper cable.
I’ve seen lots of devices whose designers took great liberty with the RS232
standard...a breakout box and some gender changers was indispensable in
working with a variety of serial devices. Sometimes even that plus a
healthy amount of experience wasn’t sufficient, as when marginal voltage
swings, extra long cables, and different ground potential at each end
conspired against you.
Lots of fun!
On Mon, Jul 9, 2018 at 10:10 AM Cady, Fred <[hidden email]> wrote:

> Thanks Don.  It must have been interesting working all that out.  I used
> to enjoy giving my students a history lesson explaining the control and
> handshaking signals in the RS232 connector from basic principles, starting
> with the Bell 103 modem.  That didn't help  explain the terminology and
> signal naming problem that Andy had. Manufacturers were terrible at keeping
> to the standard.  And really, in isolation, it doesn't make sense that a
> signal named TxD would be a input and not an output.  Documentation was
> scanty and so the scope, or my favorite test tool -- the RS232 Blinky Box
> -- had to be gotten out to tell what was what.
>
> The now  used for other purposes signals are:
> DTR -- from the terminal to the modem to tell the modem the Data Terminal
> was ready.  Now used for CW or PTT.
>
> DSR -- From the modem to the terminal to indicate the modem was ready
> (generally power on).
>
> The Bell 103 could send data only in one direction at a time so RTS and
> CTS were included to control the flow of the data.
>
> RTS -- Request to Send from the terminal to the modem to request the line.
>
> CTS -- Clear to send from the modem to the terminal to say the line was
> not busy and to go ahead with sending the data.
>
> RTS and CTS were also used to control the data flow from a fast device to
> a slow device.  I think there were some kenwood radios that used this
> scheme.
>
> DCD -- Data Carrier Detected was used for the modem to tell the terminal
> that the carrier from the other data set was being generated (the phone
> line was working).
>
> RI -- Ring Indicator asserted by the modem when it heard a ringing signal
> at the other end of the telephone line.
>
> As I remember it.
>
> Cheers,
> Fred KE7X
>
>
>
>
> ________________________________
> From: [hidden email] <[hidden email]>
> on behalf of Don Wilhelm <[hidden email]>
> Sent: Sunday, July 8, 2018 10:04 PM
> To: [hidden email]
> Subject: Re: [Elecraft] [KX3] RS232 xcvr control when serial ports are
> occupied
>
> The computer is the DTE device, and those devices designed to connect to
> the computer via the serial port are normally wired as DCE devices.
>
> The original thought when the IBM PC serial port was designed was that
> the PC would be used as a terminal connected to a modem, thus the
> decision was that the PC should be a DTE - and for the first several
> years the PC was used only as a terminal device.  Yes, I was involved
> during those early days, but not as a part of that decision making
> process - I was involved with the IBM PC modems.  My manager said I had
> "M" engraved on my forehead.
>
> Now we have the situation where the computer is the controller.  It
> would be very confusing to change the wiring of the computer, so it
> remains as a DTE, and connecting devices (while not modems) are
> configured as a DCE,
>
> 73,
> Don W3FPR
>
> On 7/8/2018 10:15 PM, Cady, Fred wrote:
> > Hi Andy,
> >
> > Don is correct.
> >
> > Here is a little blurb that might help.
> >
> >
> http://www.ke7x.com/home/miscellaneous-k3-information/unexpected-agc-behavior/rs232-interfaces-1
> >
> >
> > ________________________________
> > From: [hidden email] <[hidden email]>
> on behalf of Don Wilhelm <[hidden email]>
> > Sent: Sunday, July 8, 2018 7:21 PM
> > To: ANDY DURBIN; [hidden email]
> > Subject: Re: [Elecraft] [KX3] RS232 xcvr control when serial ports are
> occupied
> >
> > Andy,
> >
> > No TXD is TXD all the way through the path.  Yes, the DTE TXD will have
> > the drivers, and the DCE will have receivers, but it is TXD from end to
> > end.  RXD is the other way around because the DCE drives that line.
> > Trsnsmit and receive are named with respect to the DTE.
> >
> > 73,
> > Don W3FPR
> >
> > On 7/8/2018 8:39 PM, ANDY DURBIN wrote:
> >> "TXD is really pin 3."
> >>
> >>
> >> One end's TXD is the other end's RXD. That's obvious to those who have
> used RS-233 for a while but if someone needs to ask then it may not be
> obvious. Find the TXD pin on the source and connect it the RXD pin on the
> destination. Sometimes it's easier to look with a scope than to try to
> understand the documentation.
> > ______________________________________________________________
> > 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]
> >
> ______________________________________________________________
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> Post: mailto:[hidden email]
>
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> Message delivered to [hidden email]
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>
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Re: [KX3] RS232 xcvr control when serial ports are occupied

w5sum
I still use a black box brand breakout box!! Indispensable to a field communications technician!

Ronnie W5SUM

Sent from my iPhone

> On Jul 9, 2018, at 11:04 AM, Dave Fugleberg <[hidden email]> wrote:
>
> As a ‘field engineer ‘ for a global company in the 80s, I’d occasionally
> find one of those RS232 breakout boxes tucked behind some production
> system, jumpered to make the connection work, blinking away, because some
> technician finally hit upon the magic combination and then left it in place
> rather than building a proper cable.
> I’ve seen lots of devices whose designers took great liberty with the RS232
> standard...a breakout box and some gender changers was indispensable in
> working with a variety of serial devices. Sometimes even that plus a
> healthy amount of experience wasn’t sufficient, as when marginal voltage
> swings, extra long cables, and different ground potential at each end
> conspired against you.
> Lots of fun!
>> On Mon, Jul 9, 2018 at 10:10 AM Cady, Fred <[hidden email]> wrote:
>>
>> Thanks Don.  It must have been interesting working all that out.  I used
>> to enjoy giving my students a history lesson explaining the control and
>> handshaking signals in the RS232 connector from basic principles, starting
>> with the Bell 103 modem.  That didn't help  explain the terminology and
>> signal naming problem that Andy had. Manufacturers were terrible at keeping
>> to the standard.  And really, in isolation, it doesn't make sense that a
>> signal named TxD would be a input and not an output.  Documentation was
>> scanty and so the scope, or my favorite test tool -- the RS232 Blinky Box
>> -- had to be gotten out to tell what was what.
>>
>> The now  used for other purposes signals are:
>> DTR -- from the terminal to the modem to tell the modem the Data Terminal
>> was ready.  Now used for CW or PTT.
>>
>> DSR -- From the modem to the terminal to indicate the modem was ready
>> (generally power on).
>>
>> The Bell 103 could send data only in one direction at a time so RTS and
>> CTS were included to control the flow of the data.
>>
>> RTS -- Request to Send from the terminal to the modem to request the line.
>>
>> CTS -- Clear to send from the modem to the terminal to say the line was
>> not busy and to go ahead with sending the data.
>>
>> RTS and CTS were also used to control the data flow from a fast device to
>> a slow device.  I think there were some kenwood radios that used this
>> scheme.
>>
>> DCD -- Data Carrier Detected was used for the modem to tell the terminal
>> that the carrier from the other data set was being generated (the phone
>> line was working).
>>
>> RI -- Ring Indicator asserted by the modem when it heard a ringing signal
>> at the other end of the telephone line.
>>
>> As I remember it.
>>
>> Cheers,
>> Fred KE7X
>>
>>
>>
>>
>> ________________________________
>> From: [hidden email] <[hidden email]>
>> on behalf of Don Wilhelm <[hidden email]>
>> Sent: Sunday, July 8, 2018 10:04 PM
>> To: [hidden email]
>> Subject: Re: [Elecraft] [KX3] RS232 xcvr control when serial ports are
>> occupied
>>
>> The computer is the DTE device, and those devices designed to connect to
>> the computer via the serial port are normally wired as DCE devices.
>>
>> The original thought when the IBM PC serial port was designed was that
>> the PC would be used as a terminal connected to a modem, thus the
>> decision was that the PC should be a DTE - and for the first several
>> years the PC was used only as a terminal device.  Yes, I was involved
>> during those early days, but not as a part of that decision making
>> process - I was involved with the IBM PC modems.  My manager said I had
>> "M" engraved on my forehead.
>>
>> Now we have the situation where the computer is the controller.  It
>> would be very confusing to change the wiring of the computer, so it
>> remains as a DTE, and connecting devices (while not modems) are
>> configured as a DCE,
>>
>> 73,
>> Don W3FPR
>>
>>> On 7/8/2018 10:15 PM, Cady, Fred wrote:
>>> Hi Andy,
>>>
>>> Don is correct.
>>>
>>> Here is a little blurb that might help.
>>>
>>>
>> http://www.ke7x.com/home/miscellaneous-k3-information/unexpected-agc-behavior/rs232-interfaces-1
>>>
>>>
>>> ________________________________
>>> From: [hidden email] <[hidden email]>
>> on behalf of Don Wilhelm <[hidden email]>
>>> Sent: Sunday, July 8, 2018 7:21 PM
>>> To: ANDY DURBIN; [hidden email]
>>> Subject: Re: [Elecraft] [KX3] RS232 xcvr control when serial ports are
>> occupied
>>>
>>> Andy,
>>>
>>> No TXD is TXD all the way through the path.  Yes, the DTE TXD will have
>>> the drivers, and the DCE will have receivers, but it is TXD from end to
>>> end.  RXD is the other way around because the DCE drives that line.
>>> Trsnsmit and receive are named with respect to the DTE.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>>> On 7/8/2018 8:39 PM, ANDY DURBIN wrote:
>>>> "TXD is really pin 3."
>>>>
>>>>
>>>> One end's TXD is the other end's RXD. That's obvious to those who have
>> used RS-233 for a while but if someone needs to ask then it may not be
>> obvious. Find the TXD pin on the source and connect it the RXD pin on the
>> destination. Sometimes it's easier to look with a scope than to try to
>> understand the documentation.
>>> ______________________________________________________________
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>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
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>>>
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>> ______________________________________________________________
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>>
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Re: [KX3] RS232 xcvr control when serial ports are occupied

Bill Frantz
In reply to this post by Cady, Fred-2
Back in the day, I worked for Tymshare, a time sharing company
(AKA early cloud computing). We used Bell 103 protocol modems to
provide full duplex connections for our users who were using
ASCII terminals, both CRT and teleprinter. They could type at
the same time the computer was sending data, so the modem was
supporting full duplex.

I note the Wikipedia article
<https://en.wikipedia.org/wiki/Bell_103_modem> mentions:

   "The Bell 103 modem used audio frequency-shift keying to
encode data. Different pairs of audio
   frequencies were used by each station:

     The originating station used a mark tone of 1,270 Hz and a
space tone of 1,070 Hz.
     The answering station used a mark tone of 2,225 Hz and a
space tone of 2,025 Hz."

So the modem can both send and receive at the same time if the
communication link supports it.

Other terminals, such as the IBM 2741, could only handle data in
one direction and needed the RTS/CTS lines to support their needs.

And, radio applications would need separate transmit frequencies
and good filtering to support full duplex.

73 Bill AE6JV

On 7/9/18 at 8:07 AM, [hidden email] (Cady, Fred) wrote:

>The Bell 103 could send data only in one direction at a time so
>RTS and CTS were included to control the flow of the data.

---------------------------------------------------------------------------
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Re: [KX3] RS232 xcvr control when serial ports are occupied

k6dgw
In reply to this post by Don Wilhelm
The flaw is naming them "transmit" and "receive."  "DTE2DCE" and vice
versa might have been a better choice so many years ago.  "Data
Terminal" and "Data Communications" were probably equally poor naming
choices, but it seemed so obvious then.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 7/8/2018 6:21 PM, Don Wilhelm wrote:

> Andy,
>
> No TXD is TXD all the way through the path.  Yes, the DTE TXD will
> have the drivers, and the DCE will have receivers, but it is TXD from
> end to end.  RXD is the other way around because the DCE drives that
> line.
> Trsnsmit and receive are named with respect to the DTE.
>
> 73,
> Don W3FPR
>
> On 7/8/2018 8:39 PM, ANDY DURBIN wrote:
>> "TXD is really pin 3."
>>
>>
>> One end's TXD is the other end's RXD. That's obvious to those who
>> have used RS-233 for a while but if someone needs to ask then it may
>> not be obvious. Find the TXD pin on the source and connect it the RXD
>> pin on the destination. Sometimes it's easier to look with a scope
>> than to try to understand the documentation.
>

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