[aprssig] has anyone built/modified a USB to TTL level converter??

Dave dave at g8kbv.demon.co.uk
Sat Jun 4 12:45:37 EDT 2011


Bob...

There is nothing to stop you from fitting a true RS232 IO card to your 
PC.   Desktop cards, PCMCIA cards, even multi port USB devices exist, and 
all work very well.

73

Dave G0WBX


On 3 Jun 2011 at 9:19, Bob wrote:

> well, yeah,
> 
> I have an IC706 that it TTL.
> I have a MAX233 IC (TTL to RS232 level
> converter/interface/transceiver) I have a Sil Labs CP2101 already
> mounted on a small board with a USB cable, and I have the drivers for
> the CP2101. This used to be a "goezinta box" for a cell phone. 
> 
> My goal was to build, kluge together an CI/V that went from USB to TTL
> by raiding my junque box.
> 
> I have TTL to RS232 level converters that I have built in the past,
> but I have never played with USB and since all of my computers these
> days are USB and none with a real (semi real) RS232 interface, I
> brought my question to this group.
> 
>  Bob
> 
> -----Original Message-----
> From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On
> Behalf Of Greg D Sent: Friday, June 03, 2011 2:44 AM To: TAPR APRS
> Mailing List Subject: Re: [aprssig] has anyone built/modified a USB to
> TTL level converter??
> 
> Hi Bob,
> 
> Uh, let me see if I have this right...
> 
> You are trying to drive your IC706 rig from a computer. The computer
> has a regular (RS-232) serial port (or you can make one with a
> standard dongle), and the radio needs TTL. You want to connect the
> two, right?
> 
> A TTL "high" signal (+3v or so) translates to a negative half dozen
> volts or so on RS-232, and a TTL "low" (0v) maps to a positive half
> dozen volts or so on RS-232. You don't need to make this any more
> complicated than it is.
> 
> If you're halfway handy with a soldering iron, to drive the rig from
> the computer, all you need is a transistor, diode, and a resistor or
> two. Let me know if you are interested and I can dig up the schematic.
> I drive my Yaesu FT-736R like this, and it works great.
> 
> To drive the computer from the rig, it's something equally simple. The
> Yaesu rig doesn't talk back to the computer (really annoying!), but I
> think the diagram I'm remembering has both directions covered. If you
> can find the schematic for the original FODTrack satellite tracking
> controller, I believe it's in there.
> 
> Greg KO6TH
> 
> 
> Bob wrote:
> > I need TTL.
> > I have RS232
> > I have USB
> > I do not have a RS232 port. Rules out the standard USB to RS232
> > dongle.
> >
> > I think that I want to take an old cell phone to computer interface
> > that
> has
> > a USB to RS232 level converter. It is a common chip, and I have the
> drivers.
> >
> > I want to take the RS232 from the cell phone cable and feed it to a
> > MAX233 to get TTL in/out.
> >
> > Then use the TTL to talk to the IC706m2g to control the radio.
> >
> > Without reinventing the wheel, is there a "better way"?
> >
> > Bob K8YS
> >
> >
> > _______________________________________________
> > aprssig mailing list
> > aprssig at tapr.org
> > https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
> >    
> 
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