[ICOM] Opto-Isolators (Was Computer Control Interface)

[Larry Winslow]

Jim,

You'll definitely have to drive the 765 key input 
with a transistor. I struggled laboriously for 
several days trying to get an opto-isolator to 
work with my 765. I finally removed the 
opto-isolator and drove a 2n2222 transistor thru 
a 4.7k resistor - that has worked ever since.

73 - Larry WØNFU
larry_w at comcast.net

At 02:30 PM 12/28/2005, you wrote:
>Speaking of opto-isolators...
>
>I'm having a difficulty keying the key (on the straight key input) of my
>Icom 765.  The opto-isolator worked just fine with the 1000MP but not
>with the 765. I may have to install another transistor after the
>opto-isolator.
>
>Just food for thought.
>
>73
>
>Jim W7RY
>
>
>-----Original Message-----
>From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net]
>On Behalf Of Gary Fiber
>Sent: Wednesday, December 28, 2005 8:12 AM
>To: ICOM Reflector
>Subject: RE: [ICOM] Computer Control Interface
>
>Well when I was working at Icom the easiest way to provide a hard
>ground was to use a transistor externally, no mods required to the
>equipment controlling the rig. We could not suggest to the customer
>how to modify his after market equipment to make it work with Icom
>products.
>
>I looked at a HM-14 schematic, when you place a hard ground the U/D
>connection rig tunes up in frequency, when you ground through a 470
>OHM resistor the rig tunes down. I was remembering the troubles I
>went through with a customer and his DSP-2232 and using the Opto
>isolator to drive a transistor was easiest at the time. Some programs
>would control the frequency up / down mode in the DSP-2232. Others
>would use an external antenna, radio frequency controller.
>
>When I saw the schematic of the MFJ-1289 I assumed Bob might be
>experiencing the same issue since the manual reads use the CW out for
>FSK keying. I did not get into it to far though.
>I am using a Rig Blaster No Mic and just picked up a Tigertronics
>Signalink SL-1+ for my IC-718.
>
>Buxcomm has a huge site I was hoping to find the product Bob was
>using and have a look at the schematic to find any differences in the
>FSK Keying as that unit seems to work for him.
>
> >If you are using an opto to do CW keying via the UP/DOWN function,
> >then you should be aware that the UP/DOWN sensing in the Icom is
> >done by voltage.  That is, it senses the voltage on the UP/DOWN
> >line.   The UP/DOWN line is also used for the 4 voice/CW memory
> >keying but in that case, it senses 4 voltages
>
>What Icom rig uses the U/D line for Voice and CW memory keying? Must
>be the newer models as the older one didn't so far as I remember.
>
>Gary K8IZ
>
> >.  What this means is, if you are using a transistor to key that
> >line, whether it is the output of an opto or discrete transistor,
> >you have to account for the Vcesat of the transistor in presenting
> >the line with a voltage.  The UP/DOWN buttons have no voltage across
> >them when they are on.  The Vce sat could be several tenths of a
> >volt.  If you do the calculations, understanding the internal series
> >resistance that is in the radio and the unloaded voltage, you can
> >come up with 4 new values of resistance for the keyer and probably a
> >new value for the UP/DOWN.  I have done that for the keyer with
> >great success.  The only catch with the UP/DOWN, is that it only
> >uses one resistance, with the other state grounding the line.  This
> >may present a problem if the voltage detection is looking for
> >something less that the saturation voltage of the transistor.  I
> >have not done an UP/DOWN keyer, so I can't say whether it will work
> >or not, but I have done computer controlled interfaces using the
> >memory keyer with optos/transistors.
> >
> >
> >At 12/27/2005 12:42 PM, you wrote:
> > >Bob,
> > >
> > >I was looking at the MFJ-1279 schematic and the CW out is using a
> > Opto Isolator. In the past I remember an Opto isolator not being
> > able to place a hard enough ground on the Icom UP / Down input.
> > >The AEA DSP-2232 users had to install a transistor to provide hard
> > enough ground so the DSP-2232 would cause a frequency change,
> > mostly to the IC-970. This was done for Doppler shift frequency
>tracking.
> > >I looked at the Buxcomm site but he has some much stuff it would
> > take a week to find the product you are using listed.
> > >
> > >Gary K8IZ
> > >
> > >At 07:58 AM 12/27/2005, you wrote:
> > >>Ok I give up on this little project, it is quickly
> > >>becoming not worth my time.
> > >>
> > >>Is someone using an interface with an Icom PRO or II or
> > >>III that does all the soundcard modes and FSK modes along
> > >>with keying CW from A SINGLE COMM PORT that actually
> > >>works?
> > >>
> > >>I would like to know what your using so I can look into
> > >>getting one.
> > >>
> > >>What is recommended by you guys with the experience?
> > >>
> > >>
> > >>
> > >>  73 fer nw,
> > >>Bob AD5VJ
> > >
> > >----
> > >Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> > >Icom Users Net: Sundays, 1700Z, 14.316 MHz
> > >Icom FAQ: http://www.qsl.net/icom/
> >
> >----
> >Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> >Icom Users Net: Sundays, 1700Z, 14.316 MHz
> >Icom FAQ: http://www.qsl.net/icom/
>
>Gary Fiber K8IZ
>GROL PG-19-6691
>Washington State Resident
>
>
>----
>Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>Icom Users Net: Sundays, 1700Z, 14.316 MHz
>Icom FAQ: http://www.qsl.net/icom/
>
>----
>Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>Icom Users Net: Sundays, 1700Z, 14.316 MHz
>Icom FAQ: http://www.qsl.net/icom/