Geo 2.0 - USB malfunction

[wetb4igetinthewater]

I bet it's not the usb, it's the usb to serial chip. My cressi cradle has proliant chip IIRC, this one sounds like it has an ftdi one. (Cressi cradle has ir to usb too.)

You don’t think it is the cable? (Not sure what you mean by “the usb”). I doubt that Fred’s part is unreliable. I’ve developed drivers for both parts for a proprietary OS. They have different protocols over USB but both have been around a long time and considered quite robust.

 

[dmaziuk]

You don’t think it is the cable? (Not sure what you mean by “the usb”). I doubt that Fred’s part is unreliable. I’ve developed drivers for both parts for a proprietary OS. They have different protocols over USB but both have been around a long time and considered quite robust.

Most of these computers are not "devices", they're just a source of bits coming from the serial port. USB cable itself is just wires. That limits the number of potential failure points to pretty much usb-to-serial converter in the cable.

I'm sure Murphy is eager to prove me wrong.

 

[wetb4igetinthewater]

Most of these computers are not "devices", they're just a source of bits coming from the serial port. USB cable itself is just wires. That limits the number of potential failure points to pretty much usb-to-serial converter in the cable.

I'm sure Murphy is eager to prove me wrong.

While differential signaling is quite robust, there have been manufacturers that cut corners that affects signal quality. I have dealt with bad cables when I was involved with the USB-IF. Too many times. I could bug one of my former co-workers about this who created a big part of the USB 2.0 electrical compliance program for the USB-IF and get his thoughts. Ultimately, without a bus analyzer (which I own) and an oscilloscope (which I do not own), we cannot be certain. In USB, each device enumerates. In the case of the USB to RS232, the Prolific, FTDI parts have all been through the USB-IF certification program, and probably the most important aspect of which is signal quality. Now I don't have access to the eye patterns, but I'd bet a lot of money that the problems in communication is not between the host (computer) and the transceiver of the converter. RS232 protocol has been around forever.

@anchochile, if you are interested in paying for shipping to Colorado and back, I can ask my former co-worker, Jim Choate, if he'd look at it from an electrical point of view. I'd check with him first, but he'd probably take a look, as I've sent him a few contracts his way, one quite recent. LMK, as I'm quite curious.

 

[anchochile]

UPDATE! It was the cable. The free replacement cable arrived today and both dive computers synced like a dream.

Now I just have to hope that when this new USB cable fails, it will again be within the 2-year warranty, because it'll sure be hard to stomach forking over another $98. A few of those and I'm better off upgrading to a Shearwater...

 

[divinh]

UPDATE! It was the cable. The free replacement cable arrived today and both dive computers synced like a dream.

Now I just have to hope that when this new USB cable fails, it will again be within the 2-year warranty, because it'll sure be hard to stomach forking over another $98. A few of those and I'm better off upgrading to a Shearwater...

I'm going to guess the cable margins are pretty high, so you could probably get another replacement at a discount, direct, as they seem responsive.

 

[dmaziuk]

Now I just have to hope that when this new USB cable fails, it will again be within the 2-year warranty, because it'll sure be hard to stomach forking over another $98. A few of those and I'm better off upgrading to a Shearwater...

You'll just trade the FTDI/ProLiant serial->USB chip failure to whichever serial->BT(?E) chip failure. And the need for compatible BT receiver, which our next generation cellphones will hopefully have. And the next one. And the one after that...

 

[wetb4igetinthewater]

You'll just trade the FTDI/ProLiant serial->USB chip failure ...

What did I miss that points to a USB part failure?

 

[dmaziuk]

What did I miss that points to a USB part failure?

You didn't. But since "it was the cable" and the error was "device not recognized", I assume it was the "device" inside the cable that failed. Rather than a simple break or a short in the wire. And there's only one "device" in there.

 

[wetb4igetinthewater]

You didn't. But since "it was the cable" and the error was "device not recognized", I assume it was the "device" inside the cable that failed. Rather than a simple break or a short in the wire. And there's only one "device" in there.

That's kind of a big assumption with bus and oscilloscope traces. There most likely isn't a short or break in the wires. Just not manufactured to meet specifications.

Which is awfully common. Not as bad as high speed ethernet, but pretty bad. It gets worse with USB 3.x.

 

[dmaziuk]

That's kind of a big assumption with bus and oscilloscope traces. There most likely isn't a short or break in the wires. Just not manufactured to meet specifications.

Which is awfully common. Not as bad as high speed ethernet, but pretty bad. It gets worse with USB 3.x.

Well the other ass-sumption was that the cable worked before and so was up to specs until it wasn't.

And I'll see your USB 3.x and raise you an HDMI+USB KVM switch: I'm returning my 4th one and this one's a record setter: it came with USB (v.2) ports DOA. In all the others it was HDMI and it took them a couple of weeks to go titsup. One lasted the whooping! two months, even.