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

[Andrew Rich]

USB is USB
TTL is TTL
RS232 is RS232

they are different


----- Original Message ----- 
From: "Greg Dolkas" <ko6th.greg at gmail.com>
To: "TAPR APRS Mailing List" <aprssig at tapr.org>
Sent: Saturday, June 04, 2011 12:01 PM
Subject: Re: [aprssig] has anyone built/modified a USB to TTLlevel 
converter??


> Hi Bob,
>
> Ok, I think I see your question.
>
> USB is not just a signal level shift like RS-232 to TTL is.  Yes, it's 
> serial, but there's a protocol on top of it that requires some 
> intelligence at each end.  That's what is inside one of those dongles. 
> So, use a dongle to go from USB to serial, then level shift to TTL.
>
> You might be able to pick up a TTL signal from inside the dongle, 
> depending on brand and construction, but I haven't tried that.
>
> Good luck,
>
> Greg  KO6TH
>
>
> -----Original Message-----
> From: "Bob" <k8ys at fuse.net>
> To: "'TAPR APRS Mailing List'" <aprssig at tapr.org>
> Sent: 6/3/11 6:19 AM
> Subject: Re: [aprssig] has anyone built/modified a USB to TTL level 
> converter??
>
> 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 nee
>
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