> -----Original Message-----
> From: writelog-admin@contesting.com
> [mailto:writelog-admin@contesting.com]On Behalf Of Gil Baron
> Sent: Sunday, November 10, 2002 6:53 AM
> To: writelog@contesting.com; hamcat@directvinternet.com
> Subject: RE: [WriteLog] ptt resistance (part 2)
>
>
> K4SB [hamcat@directvinternet.com] SAID to me
>
>
> Well, I don't know if writelog does it, but if you just boot into
> windows, you will find that RTS is Positive, and DTR is negative. Put
> a voltmeter on the pin to ground to see it.
>
> 73
> Ed
Well as I said, on mine (WINDOWS XP-PRO) BOTH are positive.
Like I said, it is not defined.
>
>
>
>
> >From the RS232 Specs:
>
> Interface Electrical
>
> All signals are measured in reference to a common ground, which is called
> the signal ground (AB). A positive voltage between 3 and 15 Vdc
> represents a
> logical 0 and a negative voltage between 3 and 15 Vdc represents a logical
> 1.
> This switching between positive and negative is called bipolar. The zero
> state is not defined in RS232 and is considered a fault condition (this
> happens when a device is turned off).
> According to the above a maximum distance of 50 ft or 15 m. can be reached
> at a maximum speed of 20k bps. This is according to the official
> specifications, the distance can be exceeded with the use of Line
> Drivers.Functional description
>
>
> As you can see all signals use the same levels for logical one
> and zero and
> MOST IMPORTANT the zero state is UNDEFINED. That means that you must live
> with whatever you get when not running anything and THE PROGRAM must use
> logical 0 to mean 1 and logical 1 to mean zero. Since almost all
> the radios
> are set up using an NPN transistor with + into the base to key
> the radio so
> that the output goes low means that he program has to reverse the
> logic. My
> ports all have +12 when nothing is on them but they could just as
> well have
> 0 or minus 10 or whatever. This strange spec of the RS232 causes endless
> confusion :-)
>
>
>
> > -----Original Message-----
> > From: writelog-admin@contesting.com
> > [mailto:writelog-admin@contesting.com]On Behalf Of Steve Woodruff
> > Sent: Sunday, November 10, 2002 12:04 AM
> > To: writelog@contesting.com
> > Subject: [WriteLog] ptt resistance (part 2)
> >
> >
> > Ok - just when you thought this thread was dead.
> > Using WL as my voice keyer... and as of last
> > night i thought all was good. I changed the
> > circuit to be 1k ohm into a 2n2222. When WL
> > plays the ssb message, the rig trips into TX
> > and back to RX after the message is done. Ok.
> > Now today i tested it with the amp on. Oops.
> > The amp goes into TX mode as soon as i turn
> > it on -- and only goes off when i remove the
> > PTT cord that i built for WriteLog (RTS from
> > cw/serial port).
> >
> > I measure ~1450 ohms resistance when the PTT
> > is *NOT* tripped -- its not enough to keep
> > the ic706 in TX mode, but is that enough to
> > trip the amp into TX? Maybe so. I will try
> > to substitute a 2.2k ohm resistor for that
> > 1k resistor and see if it helps. I did have
> > a 4.7k resistor before -- but then i couldn't
> > even get the rig to TX via this ptt line.
> >
> > any suggestions from those WL users who've
> > gone through this before appreciated!
> >
> > tnx
> >
> > /steve n9oh
> >
> >
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> >
>
>
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