I was making the assumption that the situation in the K3S was similar to
what would happen if you tried to connect two RS-232 ports together as
would happen if you used a "Y" cable. I know that will not work, and
because one driver can be trying to drive a positive voltage on the
signal at the same time another driver is driving with a negative
voltage. Not only will that not work, but the drivers can damage each
other.
But then I do not have detailed schematics.
Lyle has responded that he has connected both the USB and an RS-232
adapter with no problems (he should know since he is one of the K3S
designers), so the implementation in the K3S apparently has designed in
protection for that situation.
Sorry if I caused alarm unnecessarily.
73,
Don W3FPR
On 9/23/2015 7:13 AM, [email protected] wrote:
The manual doesn't indicate that you can't have both the USB and RS232
connected at the same time. In fact the manual states that you can connect
the RS232 specifically for PTT. The RS232 isn't going to be used for rig
control, only PTT. If this is an unacceptable configuration on the K3S then
the book needs to be properly written.
I'll pull the covers at lunch and see what the smell is.
-----Original Message-----
From: Elecraft [mailto:[email protected]] On Behalf Of Don
Wilhelm
Sent: Wednesday, September 23, 2015 12:25 AM
To: [email protected]; [email protected]
Subject: Re: [Elecraft] K3S PTT using DTR/DTS issue
Jerry,
Did you have the USB connection to the K3S still connected while you also
connected the USB to Serial adapter into the RJ-45 dongle?
If so, that is a "No-no". RS-232 (whether from the internal K3 USB to
serial adapter or from an external adapter) is a one to one, point to point
protocol. It must have *only* one driver on the signal lines.
If you connected both at once, you had two drivers on the signal lines, and
those two drivers would "fight with one another", possibly causing damage.
When one driver is trying to send a mark, the other trying to send a space,
those two signals are of opposite polarity and can cause damage to one
another.
So whether you damaged your external USB to serial adapter or if you damaged
the internal USB to serial adapter in the K3S is indeterminate - damage
could have been done to both.
73,
Don W3FPR
On 9/22/2015 10:42 PM, [email protected] wrote:
So my new K3S is running well and I'm setting up my software and see
that it can do digital modes and control PTT using a comm port. I open
my owners manual, page 20, which says I can use that connection for
control and PTT.
I'm already using the USB for control so will just use it for PTT. I
have a USB to serial adapter so I install it, plug in the RJ47
connector to the rig, mate the DB 9 connectors and immediately smell
burning components, Quickly disconnect the DB9.
I was previously using this serial adapter successfully on a YAESU
FT-897D before I sold the rig to get the K3S.
So now the questions:
1. Why did this apparently experience an issue? I see nothing in the
manual to indicate this requires anything but a standard connection.
2. How much damage has been done to my brand new k3S using the supplied
Elecraft cable and a known good previously good USB to Serial cable
(MFJ I believe).
I'm heartsick. Being the type of person who checks and double checks
things I can find nothing wrong with what I did and yet apparently
I've damaged something.
Tomorrow I'll pull the cover and check the board.
Jerry Moore
AE4PB, K3S - S.N. 010324
An Amatuer is - Considerate, Loyal, Progressive, Friendly, Balanced,
and Patriotic.
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